The collection targets very young readers through early elementary: listed ages range from about 0–3 and 0–4 up to roughly 4–8 years, depending on the edition and format.
Most editions are about 32 pages. Board-book variations can be shorter (around 20 pages) or slightly larger (up to about 34 pages for small board editions).
Most entries are in English, and there is at least one Spanish-language board-book edition included.
Hardcover editions are commonly aimed at early readers—around 4–8 years—though some companion hardcovers are listed for younger children (about 0–4 years), depending on the title.
The Spanish edition is offered as a board-book edition.