Author/illustrator of a long list of stories for children, including four Caldecott Honor Books, Leo Lionni tells a genial tale of mouse twins who befriend a talking tree. One winter, the two mice, Willie and Winnie, come upon a snow mouse they believe is holding a broom. Surprisingly, the "broom" talks to them and tells them it is actually a tree, whose name is Woody. As Willie and Winnie's friendship with Woody unfolds, Woody teaches them about the real-life changes trees undergo throughout the seasons. An entertaining story, A Busy Year is also an informative book about nature. Lionni's characteristic collage pictures work well to illustrate how leaves grow and fall, buds swell and bloom, and fruit ripens during the life cycle of a tree.