The Best Science Fiction Stories 1950 ed Everett F. Bleiler and T.E. Dikty. Frederic Fell Inc, 1950.

n.b. a smaller volume with fewer stories was published in the UK as The Best Science Fiction Stories

Henry Kuttner. Private Eye.
Originally in Astounding Science Fiction, January 1949 (using the pseudonym ‘Lewis Padgett’)

Murray Leinster. Doomsday Deferred.
Originally in The Saturday Evening Post, September 24, 1949 (using the pseudonym ‘Will F. Jenkins’)

Theodore Sturgeon The Hurkle is a Happy Beast
Originally in The Magazine of Fantasy, Fall 1949

Clifford Simak. Eternity Lost.
Originally in Astounding Science Fiction, July 1949

Robert Spencer Carr. Easter Eggs.
Originally in The Saturday Evening Post, September 24, 1949, and variously entitled ‘Those Men From Mars’, and ‘The Invaders’ according to the ISFDB)

William H. Shiras. Opening Doors.
Originally in Astounding Science Fiction, March 1949

Robert W. Krepps Five Years in the Marmalade
Originally in Fantastic Adventures, July 1949

Ray Bradbury. Dwellers in Silence.
Originally in Planet Stories, Spring 1949

Fredric Brown. Mouse.
Originally in Thrilling Wonder Stories, June 1949

Robert Moore Williams. Refuge for Tonight.
Originally in The Blue Book Magazine, March 1949

Murray Leinster. The Life-Work of Professor Muntz.
Originally in Thrilling Wonder Stories, June 1949

John D. MacDonald Flaw
Originally in : Startling Stories, January 1949

Ray Bradbury The Man
Thrilling Wonder Stories, February 1949