Contents: Optical Instruments / essay by John W. Campbell, Jr. Nightfall / Isaac Asimov; interior artwork by Kolliker & Paul Orban Adam and No Eve / Alfred Bester; interior artwork by Charles Schneeman The Sea King's Armored Division (Part 1 of 2) / essay by L. Sprague de Camp Short-Circuited Probability / Norman L. Knight; interior artwork by Kolliker Mission / Myer Krulfeld; interior artwork by Frank Kramer Test of the Gods / Raymond F. Jones; interior artwork by Kolliker Elsewhen / Caleb Saunders (i.e. Robert A. Heinlein); interior artwork by Frank Kramer We're Not All Human / essay by John W. Campbell Jr. Brass Tacks / essay by The Editor Methuselah's Children (Part 3 of 3) / serial by Robert A. Heinlein