"Tummy time - placing a baby on his or her stomach only while awake and supervised - can help your baby develop strong neck and shoulder muscles, and promote motor skills." - Mayo Clinic And this book will keep babies' brains busy, too, while their muscles are hard at work. The high-contrast images on one side are mesmerizing because, although young babies' vision is blurry, they can see bold patterns with sharp light-dark contrast and saturated color. Babies are also hard-wired to recognize faces, so there are baby photos on the other side to delight your baby, and an embedded mirror - because babies love looking at themselves! The book can be spread out in front of them, or read like a book so you can enjoy reading time together.