After reading Margo Rabb's NYT Book Review essay about authors straddling the adult and YA markets, I went to take a look at the NYT children's bestsellers, which left me with a different question altogether: Why are Lisi Harrison's four "Clique Summer Collection" books on the "paperback books" list instead of the "series books" list? (The fifth one, Claire, is coming any day now.)

It's not that the series list is all about fantasy, because there's room for the Traveling Pants and Georgia Nicolson... (UPDATE: It's been explained to me; a series doesn't count as a series for the purposes of this list unless it's been published in both hardcover and paperback.)