365 Penguins, by the French team of Jean-Luc Fromental and Joelle Jolivet.
I remember being struck by the book when it first came out—it was a favorite of Griff's older brother, Dash, back then—and thinking that it has a lot going for it. First, there's the design: huge spreads of graphic black, white, and orange, depicting an ever-growing population of penguins sent, day by day over the course of a year, to an unsuspecting nuclear family's home. There's the learning aspect: The whole book is in fact a beautifully designed series of multiplication lessons, as the family uses math to figure out the best way to efficiently house, feed, and just plain deal with their new avian companions. There's the surprise environmentalist ending, featuring the eccentric ecologist Uncle Victor and a polar bear. There's even the Where's Waldo?-esque game the author and illustrator subtly slip in, involving a single blue-footed penguin named Chilly.
Thanks to all of that, 365 Penguins grabbed us from the start, and it's never let go. Dash still enjoys leafing through it at seven, and by the time Griff got to it, it was already on the hallowed Sendak-Dr. Seuss shelf. Which is exactly where it belongs, I think.
[Cover image courtesy of Abrams Books for Young Readers]