Part one 1920 to 1930

Part two 1931
The man who evolved / Edmond Hamilton
The Jameson Satellite / Neil R. Jones
Submicroscopic / Capt. S.P. Meek
Awlo of Ulm / Capt. S.P. Meek
Tetrahedra of space / P. Schuyler Miller
The world of the red Sun / Clifford D. Simak

Part three 1932
Tumithak of the corridors / Charles R. Tanner
The Moon era / Jack Williamson

Part four 1933
The man who awoke / Laurence Manning
Tumithak in Shawm / Capt. Charles R. Tanner

Part five 1934
Colossus / Donald Wandrei
Born of the Sun / Jack Williamson
Sidewise in time / Murray Leinster
Old Faithful / Raymond Z. Gallun

Part six 1935
The parasite planet / Stanley G. Weinbaum
Proxima Centauri / Murray Leinster
The accursed galaxy / Edmond Hamilton

Part seven 1936
He who shrank / Henry Hasse
The human pets of Mars / Leslie Frances Stone
The brain stealers of Mars / John W. Campbell, Jr.
Devolution / Edmond Hamilton
Big game / Isaac Asimov

Part eight 1937
Other eyes watching / John W. Campbell, Jr.
Minus planet / John D. Clark
Past, present, and future / Nat Schachner

Part nine 1938
The men and the mirror / Ross Rocklynne