Astounding Science Fiction December 1949 (Volume 44, Number 4)
Illustrations by Ed Cartier, Paul Orban, Hubert Rogers. Cover by Zboyan (for "The Witches of Karres")

Novelette: "The Witches of Karres" by James H. Schmitz (expanded to novel length in 1966).

Stories: "Reversion" by M. C. Pease
"A Can of Vacuum" by L. Ron Hubbard.

Serials: "Gulf" (conclusion) by Robert A. Heinlein
"…And Now You Don't" (Part 2 of 3) by Isaac Asimov ("Foundation" series; formed middle/end of Second Foundation.)

Articles: "Bacterial Time Bomb" by Arthur Dugan
"Science and 'Truth'" by Willy Ley

John W. Campbell's editorial is "Digital Computer."