Knowing that I like collage, my sister told me I needed to look at Lois Ehlert's books. The recommendation was seconded by the library reference librarian who told me "Oh, you have one of my favorite books on hold!"
And Leaf Man is gorgeous, a lovely book of collaged leaves with a light, lyrical story. I am impressed by the collages and also by the way the pages are shaped so that each page provides part of the background for the preceding page. Possibly it makes the book more vulnerable to tearing, but it is so beautiful it would be worth replacing multiple times if necessary.
Also impressive are the notes inside the jacket where Ehlert identifies the leaves, or if she can't, mentions where and when they were found.