[1] It is based on the book of the same name by Maurice Sendak and directed by Neil Affleck, Lynn Reist, and Glenn Sylvester.
It was co-produced by Nelvana Limited, Suzhou Hong Ying Animation Corporation Limited for the first two seasons and Philippine Animation Studio Inc. for the third season, produced in association with Treehouse TV and PBS.
The show that focuses on seven monsters (Brothers Two, Three, Four, Five, and Seven and Sisters One and Six), each named after a different number from one to seven, and each has unique physical characteristics.
The second season ran from November 3, 2001 to January 26, 2002, again during the PBS Kids Bookworm Bunch block.
Repeats of the second season continued until September 2004, when the PBS Kids Bookworm Bunch was discontinued.