I wonder if the same shame of narrowness can be said of "children's books"? Sure, certain children's books one outgrows. But others, say Winnie-The-Pooh or Alice, seem to still hold fascination for those older Peter Pans among us. (And let's remember Peter Pan gets mention in one of Salinger's unpublished titles.) IMHO, many of the Mr Men series also fit in this league. So I wonder if the phrase "teen books" is merely a category for the certain fiction which is pitched at a very restricted age group, and I say let those in marketing try, and let parents and teachers encourage teens to read a greater diversity.