From the inside cover:
The Justice Machine is not a complete game but a source book to be used with the Heroes Unlimited game. As a source book we present a host of heroes, villains, characters, robots, an alien world, corrupt government, a secret society, and loads of ideas for you to build a campaign. Players should feel free to use these characters and ideas as they deem appropriate. You may use them in or out of context; add them to an existing campaign or create a brand new one. Each character is designed so that they can be used as player characters or non-player characters (or both). Adapt, modify and enjoy.