Flora authored and illustrated 17 children's books under his own name between 1955 (The Fabulous Firework Family) and 1982 (Grandpa's Witched-Up Christmas). A milk crate in the Flora archives contains contracts and correspondence for each one. Most of the letters passed between the author/artist and his legendary editress, Margaret McElderry.
The crate is also stuffed with manila folders for dozens of abandoned or rejected book ideas. Walter Beartree and the Boo-Saying Whale does not have a folder, but these pencil roughs were discovered in a sketchbook from the mid-1950s.