James Tiptree Jr. is the pseudonym under which Alice B. Sheldon wrote many science fiction books. She used this pseudonym because she got much more acceptance and acclaim when considered a male author rather than was a woman. The James Tiptree Jr. Memorial Award was created to honor Alice Sheldon. Some of the books/stories she wrote under the name James Tiptree Jr. are Brightness Falls from the Air and Houston Houston Do You Read?

I remember reading an introduction to one of her books where their was a big discussion as to who exactly James Tiptree Jr was, since she never (as she was trying to hide her identity/gender) made public appearances. In this intro Robert Silverberg went on about how she could not, despite the many rumors to this effect, be a woman because no woman ever write like that. He described her "as an exemplar of manly science fiction writing - 'ineluctably masculine'."* Bet he felt stupid later on.

*the exact quote is:

"There is something ineluctably masculine about Tiptree's writing ... his work is analogous to that of Hemingway ... that prevailing masculinity about both of them -- that preoccupation with questions of courage, with absolute values, with the mysteries and passions of life and death as revealed by extreme physical tests."

Robert Silverberg, "Who Is Tiptree, What Is He?" in Warm Worlds and Otherwise by James Tiptree, Jr., (New York: Ballantine Books, 1975), pp. xii-xv, xviii. As quoted by Joanna Russ in How to Suppress Women's Writing (Austin, TX: University of Texas Press, 1983), p. 44.