From the back of the book:
"Earth's Mightiest Heroes - only the Avengers can lay claim to that proud title. They have fought the deadliest villains ever to imperil the Earth, and their adventures have spanned the limits of the Marvel Universe. Avengers Coast-to-Coast is a sourcebook that enables you to create grand new adventures for the Avengers, or to relive their great adventures of the past.
New exciting information abounds within. The Avengers Charter, detailed descriptions of both mansions and their formidable defenses, new information on security clearances and procedure, full details on the amazing Quinjets are included. The roster section includes the Avengers not in the MARVEL SUPERHEROES Advanced Set (plus some updates), their allies, such as Captain Mar-Vell, Mentor, and Firebird, and a host of villains. These unsavory types include your old favorites, like Kang, Ultron, and all the Masters of Evil (with more than ever on each), as well as new ones, such as Thanos, the Squadron Sinister, and the deadly Scourge. A 24-page adventure allows you to set up your own player characters as an Avengers expansion team! It's greatness, as only Marvel Comics and TSR can do it!
This game accessory is designed for use with the MARVEL SUPERHEROES Advanced Set. It is a 96-page book, with expanded information on the Avengers, a 24-page adventure, and a roster of Avengers and their foes."