Over in the Meadow, illustrated by Ezra Jack Keats
Olive Wadsworth originally wrote this counting rhyme (or perhaps she just wrote it down) and there are many different illustrated versions, but this one is my favorite.
Ezra Jack Keats is a marvelous artist. The colors in the collages are muted, paired perfectly with the gentle song. I love to choose this book as our bedtime story.
If you do not know the song, you can learn it from the delightful video, The Wheels on the Bus... and More Sing-Along Favorites. Not only does it contain Over in the Meadow (though with illustrations by another artist), but a fabulous rendition of The Wheels on the Bus by the Bacon Brothers. My children also particularly enjoy I Want a Dog, which is one of those few instances where the video is better than the book. (I could live without There Was an Old Lady Who Swallowed a Fly, but the kids like that one, too.)