Editions are available in Hardcover, Paperback, and Board Book formats.
Suggested ages across editions span from 0–2 years up through 5–8 years, with many editions aimed at preschool and early elementary readers.
There is a board-book bedtime edition aimed at 0–2 years that is simplified for the youngest readers and contains 18 pages.
Some editions include bilingual flip-over text (English and Spanish), nonfiction backmatter with additional facts, glossaries, and lists of resources for further reading.
The bedtime board-book edition is described as a one-minute bedtime story (or up to five minutes if reread) and the edition contains 18 pages.