Knight, Damon. "What Rough Beast"
Summary: A man from Novo Russie has the mental power to fix things by altering the events that caused them.
Published: In The Magazine of Fantasy and Science Fiction, February 1959; Best from Fantasy and Science Fiction: 9 (ed. Robert P. Mills), Doubleday 1958, Ace 1959; v.t. Flowers for Algernon and Other Stories, [[publ. unknown]]; Off Center / The Rithian Terror, Ace 1965; Off Center, Gollancz 1969 and Award/Tandem [[date unknown]]; Isaac Asimov Presents the Great SF Stories: 21 (1959) (eds. Isaac Asimov and Martin H. Greenberg), DAW 1990 (0886774284); and Futures Past (eds. Jack Dann and Gardner Dozois), q.v.