From the back of the book...
Palladium Books Presents: Aliens Unlimited
Includes Rifts conversion notes. Adaptable to Rifts. Mechanoids, and Rifts Dimension Book.
> Over 100 specific alien races and monsters!
> Random alien creation tables and rules.
> New super powers, bionic and skills.
> High-tech weapon and equipment.
> Spaceships and creation rules.
> U.F.O. watch groups.
> Secret Organizations and spies.
> Rifts conversion notes. Adaptable to Rifts, Mechanoids, Rifts Dimension Book Two: Phase World and the entire Palladium Megaverse.
> Enough ideas and information to create dozens of campaigns.
> Written by Wayne Breaux and Kevin Siembieda.