Non 3-Dimensional Space
; Flatland (1884) by Edwin A. Abbott : A classic tale of a two-dimensional being meeting 'A Sphere'
; ...And He Built a Crooked House (1941) by Robert Heinlein : Story of a house that extends into the fourth dimension, much to the puzzlement of its occupants
Robot Stories
;Robbie (1939) by Isaac Asimov : First Robot story by Isaac Asimov, published in the September 1940 issue of Super Science Stories.
;Run Around (1942) by Isaac Asimov : First story to list the Three Laws of Robotics, published in the March 1942 issue of Astounding.
Time Travel
;The Chronic Argonauts (1895) by H.G. Wells : Probably the very first significant time travel story ever
;All You Zombies... (1959) by Robert Heinlein : A story featuring a neatly tangled set of time travel paradoxes
;Ripples in the Dirac Sea (1988) by Geoffrey A. Landis : The affecting story of a scientist seesawing inescapably through time, this brilliant work effectively deconstructs most time-travel stories that came before. Winner of the 1989 Nebula Award for best short story.
(Note: This list may be more appropriate as a list of Significant Science Fiction Themes)