You can't go wrong with Eric Carle, and this one is a classic. I began reading it to my twins when they were 6 months and they instantly loved it. I also used to teach kindergarten and did an entire unit based on this book. The kids learned the days of the week, foods, and the life cycle of a caterpillar, all in one book!
This is one of my all-time favorite board books for children. It's a simple story about a hungry caterpillar who eats a lot. I must have read this book at least 50 times to my child and she still didn't tire of it. Now she reads it to herself though. The drawings are great. So great in fact that there is a whole market out there of clothing, bags, games, and whatnot with the pictures from the book. It's neat how there is a hole in the middle of the food to show the caterpillar ate through it. I think young children will get a big kick out of the book.
This is a great book to introduce little ones to the remarkable things that God has created. It takes a little caterpillar through a LOT of food. He then creates his chrysallis, and shortly thereafter awakens to being a beautiful butterfly.