At SLJ's "Day of Dialog" this week, I was part of a panel about so-called "tweens" - who they are, how we can serve them as librarians, and why and how we write books for them. (By the way, "tweens" is a word I don't much like, now that I know it was invented by the advertising industry to identify a new target group.) Our moderator, Vicky Smith of Kirkus , and my terrific co-panelists, authors Gennifer Choldenko, Tim Green, Robie Harris, and the children's librarian Lisa von Drasek, gave me much to think about. At one point Lisa nudged me and showed me a poem by Billy Collins that she'd marked in a book. It's wonderfully true (in my experience), and I thought I'd share it here. On Turning Ten The whole idea of it makes me feel like I'm coming down with something, something worse than any stomach ache or the headaches I get from reading in bad light-- a kind of measles of the spirit, a mumps of the psyche, a disfiguring chick...