Lot of 20 Science Fiction Books (Heinlein/Pournelle/Niven/Herbert/GRRM/Zahn+)
Footfall by Larry Niven & Jerry Pournelle. Stranger in a Strange Land by Robert Heinlein. Conquerors' Pride by Timothy Zahn. Flatlander (aka The Long Arm of Gil Hamilton) by Larry Niven. Mag Force 7 #1: Knights of the Black Earth & Don Perrin.