The Gossip Girl.(Cecily von Ziegesar)

Byline: Henry Alford

Pssst. Check out what happens when you tell Cecily von Ziegesar, who writes those dishy, New York Times No. 1 best-selling Gossip Girl books for tween girls, how you saw a flyer for an upcoming reading she's giving in the library of Irvington, the tiny, one-hour-up-the-Hudson-from-Manhattan town where she lives. "Oh my God!" she gasps, caught off guard. "Do you know when that is? I don't have a datebook. I figured I'd just call them the first of the month." So I guess now we know why Irvington is named after the author of "The Legend of Sleepy Hollow."

But let's not be total snipesters here. I mean, what's cool about von Ziegesar is that, despite her lilac-scented upbringing-I'm just going to dangle the words "equestrienne," "Connecticut," and "Nightingale-Bamford School" in front of you here-her datebook-deprived randomness is one of the very few traits that she seems to share with the mercenary, hedonistic, Prada-clad Manhattan teenagers she writes about. In person, the 35-year-old mother of two (Oscar, one, and Agnes, four; ...