Personalized books are everywhere, but just how often are they written by best-selling children's authors? Fans of Sandra Boynton's clever and well-illustrated board books — The Belly Button Book and Snuggle Puppy being two of her most popular ones — can now give their tots a truly one-of-a-kind masterpiece created by the children's book superstar. For the author's latest book, Are You A Cow? ($20), parents and gift-givers can provide a lil one's name and two photographs to have the tome's text and dedication line customized specifically for the budding literary connoisseur. The entire book can be previewed online prior to purchasing, allowing grown-ups to see just where junior's face will appear among the cows, penguins, and hippos that grace the funny book's pages.