From publisher blurb:
The Mentalist is a new class for the Center Space or other OGL games. It is the third of a four volume series--each presenting new psionically themed classes and races. Volume 3 introduces the Mentalist class, which uses their insight and senses to enhance their combat abilities and skills. This volume does not require Volume 1 or 2 to use.
Volume 3 includes:
The Mentalist class (more or less a replacement of the Unseen class).
Mentalists choose one of four specializations:
The Detective--an expert who uses their keen insight to acquire information.
The Sneak--a rogue who uses their uncanny senses to keep out of sight.
The Con--a charlatan who uses their powers of observation to deceive others.
The Mystic--a psychic who uses their deep insight speak to spirits and manipulate minds.
One new race--the Sissith: a race of cunning and stealthy assassins.