Travel Between the Lines Adult Coloring Books are the brainchild of Geoff and Katie Matthews. Geoff and Katie met in Taiwan in 2006 and have been traveling ever since. Permanent nomads since 2013, they have visited, photographed, and tasted beer in more than 50 countries across the Americas, Europe, and Asia, with no intention of slowing down. Wandertooth started as Geoff and Katie’s personal blog to (sporadically) chronicle their adventures. It is now a home for their adult coloring book, future Travel Between the Lines books and products, and the travel-coloring community (that’s a thing, right?). In case you were wondering, a wandertooth is a noun – you know, like a person, place, or thing. In this case, it’s a thing. Like a sweet tooth, only with travely goodness instead of sugary goodness. It’s a fondness or desire for wandering or travel; an unquenchable desire; a craving that — once satisfied — only leaves you salivating for more.