He only had a few hits in the 1950s and early '60s, but as Bo Diddley sang, "You Can't Judge a Book by Its Cover." You can't judge an artist by his chart success, either, and Diddley produced greater and more influential music than all but a handful of the best early rockers. The Bo Diddley beat -- bomp, ba-bomp-bomp, bomp-bomp -- is one of rock & roll's bedrock rhythms, showing up in the work of Buddy Holly, the Rolling Stones, and even pop-garage knock-offs like the Strangeloves' 1965 hit "I Want Candy." Diddley's hypnotic rhythmic attack and declamatory, boasting vocals stretched back as far as Africa for their roots, and looked as far into the future as rap. His trademark otherworldly vibrating, fuzzy guitar style did much to expand the instrument's power and range. But even more important, Bo's bounce was fun and irresistibly rocking, with a wisecracking, jiving tone that epitomized rock & roll at its most humorously outlandish and freewheeling.

Before taking up blues and R&B, Diddley had studied classical violin, but shifted gears after hearing John Lee Hooker. In the early '50s, he began playing with his longtime partner, maraca player Jerome Green, to get what Bo's called "that freight train sound." Billy Boy Arnold, a fine blues harmonica player and singer in his own right, was also playing with Diddley when the guitarist got a deal with Chess in the mid-'50s (after being turned down by rival Chicago label Vee-Jay). His very first single, "Bo Diddley"/"I'm a Man" (1955), was a double-sided monster. The A-side was soaked with futuristic waves of tremolo guitar, set to an ageless nursery rhyme; the flip was a bump-and-grind, harmonica-driven shuffle, based around a devastating blues riff. But the result was not exactly blues, or even straight R&B, but a new kind of guitar-based rock & roll, soaked in the blues and R&B, but owing allegiance to neither.

Diddley was never a top seller on the order of his Chess rival Chuck Berry, but over the next half-dozen or so years, he produced a catalog of classics that rival Berry's in quality. "You Don't Love Me," "Diddley Daddy," "Pretty Thing," "Diddy Wah Diddy," "Who Do You Love?," "Mona," "Road Runner," "You Can't Judge a Book by Its Cover" -- all are stone-cold standards of early, riff-driven rock & roll at its funkiest. Oddly enough, his only Top 20 pop hit was an atypical, absurd back-and-forth rap between him and Jerome Green, "Say Man," that came about almost by accident as the pair were fooling around in the studio.

As a live performer, Diddley was galvanizing, using his trademark square guitars and distorted amplification to produce new sounds that anticipated the innovations of '60s guitarists like Jimi Hendrix. In Great Britain, he was revered as a giant on the order of Chuck Berry and Muddy Waters. The Rolling Stones in particular borrowed a lot from Bo's rhythms and attitude in their early days, although they only officially covered a couple of his tunes, "Mona" and "I'm Alright." Other British R&B groups like the Yardbirds, Animals, and Pretty Things also covered Diddley standards in their early days. Buddy Holly covered "Bo Diddley" and used a modified Bo Diddley beat on "Not Fade Away"; when the Stones gave the song the full-on Bo treatment (complete with shaking maracas), the result was their first big British hit.

The British Invasion helped increase the public's awareness of Diddley's importance, and ever since then he's been a popular live act. Sadly, though, his career as a recording artist -- in commercial and artistic terms -- was over by the time the Beatles and Stones hit America. He would record with ongoing and declining frequency, but after 1963, he never wrote or recorded original material on par with his early classics. Whether he'd spent his muse, or just felt he could coast on his laurels, is hard to say. But he remains a vital part of the collective rock & roll consciousness, and occasionally reached wider visibility via a 1979 tour with the Clash, a cameo role in the film Trading Places, a late-'80s tour with Ronnie Wood, and a 1989 television commercial for sports shoes with star athlete Bo Jackson. ~ Richie Unterberger

Muddy Waters was the single most important artist to emerge in post-war American blues. A peerless singer, a gifted songwriter, an able guitarist, and leader of one of the strongest bands in the genre (which became a proving ground for a number of musicians who would become legends in their own right), Waters absorbed the influences of rural blues from the Deep South and moved them uptown, injecting his music with a fierce, electric energy and helping pioneer the Chicago Blues style that would come to dominate the music through the 1950s, ‘60s, and '70s. The depth of Waters' influence on rock as well as blues is almost incalculable, and remarkably, he made some of his strongest and most vital recordings in the last five years of his life.

Waters was born McKinley Morganfield, and historians argue about some details of his early life; while he often told reporters he was born in Rolling Fork, Mississippi on April 4, 1915, researchers have uncovered census records and personal documents that would pin the year of his birth at 1913 or 1914, and others have cited the place of his birth as Jug's Corner, a town in Mississippi's Issaquena County. What is certain is that Morganfield's mother died when he just three years old, and from then on he was raised on the Stovall Plantation in Clarksdale, Mississippi by his grandmother, Della Grant. Grant is said to have given young Morganfield the nickname "Muddy" because he liked to play in the mud as a boy, and the name stuck, with "Water" and "Waters" being tacked on a few years later. The rural South was a hotbed for the blues in the '20s and ‘30s, and young Muddy became entranced with the music when he discovered a neighbor had a phonograph and records by the likes of Blind Lemon Jefferson, Lonnie Johnson, and Tampa Red.

As Muddy became more deeply immersed in the blues, he took up the harmonica; he was performing locally at parties and fish fries by the age of 13, sometimes with guitarist Scott Bohanner, who lived and worked in Stovall. In his early teens, Muddy was introduced to the sound of contemporary Delta blues artists, such as Son House, Robert Johnson, and Charley Patton; their music inspired Waters to switch instruments, and he bought a guitar when he was 17, learning to play in the bottleneck style. Within a few years, he was performing on his own and with a local string band, the Son Simms Four; he also opened a juke joint on the Stovall grounds, where fellow sharecroppers could listen to music, enjoy a drink or a snack, and gamble. Waters became a fixture in Mississippi, performing with the likes of Big Joe Williams and Robert Nighthawk, and in the late summer of 1941, musical archivists Alan Lomax and John Work III arrived in Mississippi with a portable recording rig, eager to document local blues talent for the Library of Congress (it's said they were hoping to locate Robert Johnson, only to learn he had died three years earlier). Lomax and Work were strongly impressed with Waters, and recorded several sides of him performing in his juke joint; two of the songs were released as a 78, and when Waters received two copies of the single and $20 from Lomax, it encouraged him to seriously consider a professional career. In July 1943, Lomax returned to record more material with Waters; these early sessions with Lomax were collected on the album Down On Stovall's Plantation in 1966, and a 1994 reissue of the material, The Complete Plantation Recordings, won a Grammy award.

In 1943, Waters decided to pull up stakes and relocate to Chicago, Illinois in hopes of making a living off his music. (He moved to St. Louis for a spell in 1940, but didn't care for it.) Waters drove a truck and worked at a paper plant by day, and at night struggled to make a name for himself, playing house parties and any bar that would have him. Big Bill Broonzy reached out to Waters and helped him land better gigs; Muddy had recently switched to electric guitar to be better heard in noisy clubs, which added a new power to his cutting slide work. By 1946, Waters had come to the attention of Okeh Records, who took him into the studio to record but chose not to release the results. A session that same year for 20th Century Records resulted in just one tune being issued as the B-side of a James "Sweet Lucy" Carter release, but Waters fared better with Aristocrat Records, a Chicago-based label founded by brothers Leonard and Phil Chess. The Chess Brothers began recording Waters in 1947, and while a few early sides with Sunnyland Slim failed to make an impression, his second single for Aristocrat as a headliner, "I Can't Be Satisfied" b/w "(I Feel Like) Goin' Home," became a significant hit and launched Waters as a star on the Chicago blues scene.

Initially, the Chess Brothers recorded Waters with trusted local musicians (including Earnest "Big" Crawford and Alex Atkins), but for his live work, Waters had recruited a band which included Little Walter on harmonica, Jimmy Rogers on guitar, and Baby Face Leroy Foster on drums (later replaced by Elgin Evans), and in person, Waters and his group earned their reputation as the most powerful blues band in town, with Waters' passionate vocals and guitar matched by the force of his combo. By the early '50s, the Chess Brothers (who had changed the name of their label from Aristocrat to Chess Records in 1950) began using Waters' stage band in the studio, and Little Walter in particular became a favorite with blues fans and a superb foil for Waters. Otis Spann joined Waters' group on piano in 1953, and he would become the anchor for the band well into the '60s, after Little Walter and Jimmy Rogers had left to pursue solo careers. In the '50s, Waters released some of the most powerful and influential music in the history of electric blues, scoring hits with numbers like "Rollin' and Tumblin,'" "I'm Ready," "I'm Your Hoochie Coochie Man," "Mannish Boy," "Trouble No More," "Got My Mojo Working," and "I Just Want to Make Love to You" which made him a frequent presence on the R&B charts.

By the end of the '50s, while Waters was still making fine music, his career was going into a slump. The rise of rock & roll had taken the spotlight away from more traditional blues acts in favor of younger and rowdier acts (ironically, Waters had headlined some of Alan Freed's early "Moondog" package shows), and Waters' first tour of England in 1958 was poorly received by many U.K. blues fans, who were expecting an acoustic set and were startled by the ferocity of Waters' electric guitar. Waters began playing more acoustic music informed by his Mississippi Delta heritage in the years that followed, even issuing an album titled Muddy Waters: Folk Singer in 1964. However, the jolly irony was that British blues fans would soon rekindle interest in Waters and electric Chicago blues; as the rise of the British Invasion made the world aware of the U.K. rock scene, the nascent British blues scene soon followed, and a number of Waters' U.K. acolytes became international stars, such as Eric Clapton, John Mayall, Alexis Korner, and a modestly successful London act who named themselves after Muddy's 1950 hit "Rollin' Stone." While Waters was still leading a fine band that delivered live (and included the likes of Pinetop Perkins on piano and James Cotton on harmonica), Chess Records was moving more toward the rock, soul, and R&B marketplace, and seemed eager to market him to white rock fans, a notion that reached its nadir in 1968 with Electric Mud, in which Waters was paired up with a psychedelic rock band (featuring guitarists Pete Cosey and Phil Upchurch) for rambling and aimless jams on Waters' blues classics. 1969's Fathers and Sons was a more inspired variation on this theme, with Waters playing alongside reverential white blues rockers such as Mike Bloomfield and Paul Butterfield; 1971's The London Muddy Waters Sessions was less impressive, featuring fine guitar work from Rory Gallagher but uninspired contributions from Steve Winwood, Rick Grech, and Georgie Fame.

Curiously, while Chess Records helped Waters make some of the finest blues records of the '50s and ‘60s, it was the label's demise that led to his creative rebirth. In 1969, the Chess Brothers sold the label to General Recorded Tape, and the label went through a long, slow commercial decline, finally folding in 1975. (Waters would become one of several Chess artists who sued the label for unpaid royalties in its later years.) Johnny Winter, a longtime Waters fan, heard the blues legend was without a record deal, and was instrumental in getting Waters signed to Blue Sky Records, a CBS-distributed label that had become his recording home. Winter produced the sessions for Waters' first Blue Sky release, and sat in with a band comprised of members of Waters' road band (including Bob Margolin and Willie "Big Eyes" Smith) along with James Cotton on harp and Pinetop Perkins on piano. 1977's Hard Again was a triumph, sounding as raw and forceful as Waters' classic Chess sides, with a couple extra decades of experience informing his performances, and it was rightly hailed as one of the finest albums Waters ever made while sparking new interest in his music. (It also earned him a Grammy award for Best Traditional or Ethnic Folk Recording.) Waters also dazzled music fans when he appeared at the Band's celebrated farewell concert on Thanksgiving 1976 at the invitation of Levon Helm, who had helped produce one of his last Chess releases, The Muddy Waters Woodstock Album. Muddy delivered a stunning performance of "Mannish Boy" that became one of the highlights of Martin Scorsese's 1978 concert film The Last Waltz. Between Hard Again and The Last Waltz, Waters enjoyed a major career boost, and he found himself touring again for large and enthusiastic crowds, sharing stages with the likes of Eric Clapton and the Rolling Stones, and cutting two more well-received albums with Winter as producer, 1978's I'm Ready and 1981's King Bee, as well as a solid 1979 concert set, Muddy "Mississippi" Waters Live. Waters' health began to fail him in 1982, and his final live appearance came in the fall of that year, when he sang a few songs at an Eric Clapton show in Florida. Waters died quietly of heart failure at his home in Westmont, Illinois on April 30, 1983. Since then, both Chicago and Westmont have named streets in Muddy's honor, he's appeared on a postage stamp, a marker commemorates the site of his childhood home in Clarksdale, and he appeared as a character in the 2008 film Cadillac Records, played by Jeffrey Wright. ~ Mark Deming

In the history of the blues, there has never been anyone quite like the Howlin' Wolf. Six foot three and close to 300 pounds in his salad days, the Wolf was the primal force of the music spun out to its ultimate conclusion. A Robert Johnson may have possessed more lyrical insight, a Muddy Waters more dignity, and a B.B. King certainly more technical expertise, but no one could match him for the singular ability to rock the house down to the foundation while simultaneously scaring its patrons out of its wits.

He was born in West Point, MS, and named after the 21st President of the United States (Chester Arthur). His father was a farmer and Wolf took to it as well until his 18th birthday, when a chance meeting with Delta blues legend Charley Patton changed his life forever. Though he never came close to learning the subtleties of Patton's complex guitar technique, two of the major components of Wolf's style (Patton's inimitable growl of a voice and his propensity for entertaining) were learned first hand from the Delta blues master. The main source of Wolf's hard-driving, rhythmic style on harmonica came when Aleck "Rice" Miller (Sonny Boy Williamson) married his half-sister Mary and taught him the rudiments of the instrument. He first started playing in the early '30s as a strict Patton imitator, while others recall him at decade's end rocking the juke joints with a neck-rack harmonica and one of the first electric guitars anyone had ever seen. After a four-year stretch in the Army, he settled down as a farmer and weekend player in West Memphis, AR, and it was here that Wolf's career in music began in earnest.

By 1948, he had established himself within the community as a radio personality. As a means of advertising his own local appearances, Wolf had a 15-minute radio show on KWEM in West Memphis, interspersing his down-home blues with farm reports and like-minded advertising that he sold himself. But a change in Wolf's sound that would alter everything that came after was soon in coming because when listeners tuned in for Wolf's show, the sound was up-to-the-minute electric. Wolf had put his first band together, featuring the explosive guitar work of Willie Johnson, whose aggressive style not only perfectly suited Wolf's sound but aurally extended and amplified the violence and nastiness of it as well. In any discussion of Wolf's early success both live, over the airwaves, and on record, the importance of Willie Johnson cannot be overestimated.

Wolf finally started recording in 1951, when he caught the ear of Sam Phillips, who first heard him on his morning radio show. The music Wolf made in the Memphis Recording Service studio was full of passion and zest and Phillips simultaneously leased the results to the Bihari Brothers in Los Angeles and Leonard Chess in Chicago. Suddenly, Howlin' Wolf had two hits at the same time on the R&B charts with two record companies claiming to have him exclusively under contract. Chess finally won him over and as Wolf would proudly relate years later, "I had a 4,000 dollar car and 3,900 dollars in my pocket. I'm the onliest one drove out of the South like a gentleman." It was the winter of 1953 and Chicago would be his new home.

When Wolf entered the Chess studios the next year, the violent aggression of the Memphis sides was being replaced with a Chicago backbeat and, with very little fanfare, a new member in the band. Hubert Sumlin proved himself to be the Wolf's longest-running musical associate. He first appears as a rhythm guitarist on a 1954 session, and within a few years' time his style had fully matured to take over the role of lead guitarist in the band by early 1958. In what can only be described as an "angular attack," Sumlin played almost no chords behind Wolf, sometimes soloing right through his vocals, featuring wild skitterings up and down the fingerboard and biting single notes. If Willie Johnson was Wolf's second voice in his early recording career, then Hubert Sumlin would pick up the gauntlet and run with it right to the end of the howler's life.

By 1956, Wolf was in the R&B charts again, racking up hits with "Evil" and "Smokestack Lightnin'." He remained a top attraction both on the Chicago circuit and on the road. His records, while seldom showing up on the national charts, were still selling in decent numbers down South. But by 1960, Wolf was teamed up with Chess staff writer Willie Dixon, and for the next five years he would record almost nothing but songs written by Dixon. The magic combination of Wolf's voice, Sumlin's guitar, and Dixon's tunes sold a lot of records and brought the 50-year-old bluesman roaring into the next decade with a considerable flourish. The mid-'60s saw him touring Europe regularly with "Smokestack Lightnin'" becoming a hit in England some eight years after its American release. Certainly any list of Wolf's greatest sides would have to include "I Ain't Superstitious," "The Red Rooster," "Shake for Me," "Back Door Man," "Spoonful," and "Wang Dang Doodle," Dixon compositions all. While almost all of them would eventually become Chicago blues standards, their greatest cache occurred when rock bands the world over started mining the Chess catalog for all it was worth. One of these bands was the Rolling Stones, whose cover of "The Red Rooster" became a number-one record in England. At the height of the British Invasion, the Stones came to America in 1965 for an appearance on ABC-TV's rock music show, Shindig. Their main stipulation for appearing on the program was that Howlin' Wolf would be their special guest. With the Stones sitting worshipfully at his feet, the Wolf performed a storming version of "How Many More Years," being seen on his network-TV debut by an audience of a few million. Wolf never forgot the respect the Stones paid him, and he spoke of them highly right up to his final days.

Dixon and Wolf parted company by 1964 and Wolf was back in the studio doing his own songs. One of the classics to emerge from this period was "Killing Floor," featuring a modern backbeat and a incredibly catchy guitar riff from Sumlin. Catchy enough for Led Zeppelin to appropriate it for one of their early albums, cheerfully crediting it to themselves in much the same manner as they had done with numerous other blues standards. By the end of the decade, Wolf's material was being recorded by artists including the Doors, the Electric Flag, the Blues Project, Cream, and Jeff Beck. The result of all these covers brought Wolf the belated acclaim of a young, white audience. Chess' response to this was to bring him into the studio for a "psychedelic" album, truly the most dreadful of his career. His last big payday came when Chess sent him over to England in 1970 to capitalize on the then-current trend of London Session albums, recording with Eric Clapton on lead guitar and other British superstars. Wolf's health was not the best, but the session was miles above the earlier, ill-advised attempt to update Wolf's sound for a younger audience.

As the '70s moved on, the end of the trail started coming closer. By now Wolf was a very sick man; he had survived numerous heart attacks and was suffering kidney damage from an automobile accident that sent him flying through the car's windshield. His bandleader Eddie Shaw firmly rationed Wolf to a meager half-dozen songs per set. Occasionally some of the old fire would come blazing forth from some untapped wellspring, and his final live and studio recordings show that he could still tear the house apart when the spirit moved him. He entered the Veterans Administration Hospital in 1976 to be operated on, but never survived it, finally passing away on January 10th of that year.

But his passing did not go unrecognized. A life-size statue of him was erected shortly after in a Chicago park. Eddie Shaw kept his memory and music alive by keeping his band, the Wolf Gang, together for several years afterward. A child-education center in Chicago was named in his honor and in 1980 he was elected to the Blues Foundation Hall of Fame. In 1991, he was inducted into the Rock and Roll Hall of Fame. A couple of years later, his face was on a United States postage stamp. Howlin' Wolf is now a permanent part of American history. ~ Cub Koda