Big Bird's Busy Book is a 96-page book of activities and stories featuring the Sesame Street cast. Published in 1975, this is a good example of the level of work the Sesame producers would put into the tie-in books and records in the early '70s. Joe Mathieu contributed a few activity pages: "Build a Better Bird Feeder," "Ernie Plants a Garden," "The Amazing Mumford's Amazing Color Trick," "Bert's Box Town Neighborhood," and "Ernie's Mixed-Up Friends." Many of the stories and activities from this book were reprinted later in The Sesame Street Library and The Sesame Street Treasury series.