Head-to-head competition in literature isn’t anything new, but the idea of pitting two characters/things against each other in the title of a book is a continuing trend in children’s literature (and perhaps literature in general).
While it’s far from the first book to bring out the “vs.”, I think the book that really helped put it into the zeitgeist was Chris Barton and Tom Lichtenheld’s popular Shark vs. Train, released in 2010. The growth of the “versus” title makes sense – it’s an intriguing set up. What are they fighting about? Who would win?
In recent years (and upcoming in 2014) the “versus” have continued:
And possibly my favorite:
Want further proof of the rise of the “versus”? Check out this data from Google’s Ngram Viewer, which tracks word usage in books: