The listings identify Partypooper as book #20 in the series.
The listings include hardcover and paperback formats and show editions in English and Spanish.
Most listings target children around 8–12 years; some specify 9–12 years and one listing shows a broader 13–19 years range.
Books are shown with sequential series numbers (for example, the set lists books #1 through #20, with Partypooper labeled #20).
Review summaries say the books are enjoyable and engaging for children, often funny and easy for kids to pick up and read.