There was an interesting article over on the Book Riot site recently, about what is the longest YA Book Series, based on either the number of books or the page count. It's a trickier one to call than you might expect -- for instance, do you include prequels? And how do you gauge word count as opposed to page count? And the limits are obviously defined by those series that the person writing the article is familiar with, and also how they define a YA series -- thus, my Cirque Du Freak series is included (although the Mr Crepsley prequel books are not factored in), while my Demonata and Zom-B series are not, even though I would say that CDF might more accurately be described as a middle grade series, while the other two are definitely YA.

Anyway, the whole point of an article like this is to get people talking and arguing, so the end result should be seen more as a conversation piece than a definitive answer. I certainly enjoyed it, and admired the compiler's attempts to be as comprehensive as possible, even though it's a mercurial task. To find out what answers Book Riot came up with, and to compare them with your own, click here: https://bookriot.com/2019/05/02/longest-ya-book-series/