From the back cover:
I know you want to find a sidekick. After all, everyone's doing it. All the cool superheroes have them. Hey. . . I'll even give you your first one for free.
Come on kid, take one. You want people to like you, don't you?
Roll Call 2: The Sidekick's Club presents a dozen bold adventurers and their stalwart companions that you can drop into any Silver Age Sentinels campaign.
Includes character bios, dual-stat write-ups for the Tri-Stat and d20 Systems, and game seeds to kick-start your creativity.