Book 32: Otis, By Loren Long, published by Philomel Books 2009. Preschool to elementary.
This is one of the books that I bought solely because I love, love, LOVE the artwork. Loren Long used a subdued color palette to create gorgeous, retro illustrations. Otis the tractor charmingly goofy (or goofily charming), and the calf from the back view looks almost exactly like my dog Sophie did when she was a puppy -- She's a fawn-colored Ridgeback and her ears used to stick almost straight out.
The story is timeless: Friends stick with you, friends help you out, friends make you feel special; so although this theme is used frequently in children's stories, I don't find it tired. And the story is well-told, and not overdone.
This book is a must for any child interested in vintage vehicles from the '40s and '50s and appreciates a sweet story. Some of the renderings were accurate enough for my husband to identify them and he has restored two vintage cars and a truck.