Kid book recommendations?

My five-year-old son, Ben, did his first word search puzzle at kindergarten yesterday. And you know what word searches are, don't you? That's right: the gateway drug to crosswords.

He'll be getting Helene Hovanec's My First Puzzles: Easy First Puzzles for Christmas. In the meantime, can you recommend any great puzzle books for young kids? Keep in mind that Ben can't exactly read yet, but I've let him slide for long enough. It's time he joined the world of word games.

(And if it's a book you created or edited, please don't be shy about recommending it if it's appropriate for kindergartners.)