WILLEMS, Mo. The Thank You Book. illus. by Mo Willems. 64p. (An Elephant & Piggie Book). Disney-Hyperion. May 2016. Tr $9.99. ISBN 9781423178286. PreS-Gr 2–A sweet and pitch-perfect swan song to a wildly popular series. Reflecting on her good fortune and many blessings, Piggie decides to thank everyone who is important to her. Gerald thinks this is a bad idea, in that she runs the very big risk of forgetting someone. Piggie will not be dissuaded and embarks on her “Thank-o-rama!” She gives a shout-out to the Squirrels, Snake, the Pigeon, and other characters from the series, including Mouse, Birdies, Rhino, Hippo, Hippo’s Big Sister, Barky Dog, Pelican, Bears, and Worms. Piggie turns into a thanking machine. Whale, Ice Cream Penguin, Doctor Cat, and Brian Rat all make appearances. Last, but hardly least, she remembers to acknowledge her partner in crime, Gerald, but there’s still one important group that the effusive Piggie neglects to mention—their readers! Willems’s brilliant minimalist cartoon illustrations are as expressive and charming as ever. VERDICT The 25th installment in the winning series is a must-have for every collection and will lead kids to go back and revisit the earlier titles again and again. Thanks, Mo Willems, you’ve helped a whole generation learn to be proficient readers with Gerald & Piggie. Hugs all around!–Luann Toth, School Library Journal