I've always enjoyed this classic book by Eric Carle. The illustrations are so neat, the way the book gets bigger or "grows" each day is really cool. This is a good book to teach the days of the week, counting, colors..many different things. This book could even be a starter for a lesson on caterpillars and the way they grow and eventually turn into butterflies. There are many opportunities for classroom use with this book. {Grade Level: K-1st}