Michael Raymond Donald Ashley (born 1948) is a British bibliographer, author and editor of science fiction, mystery, and fantasy.
He edits the long-running Mammoth Book series of short story anthologies, each arranged around a particular theme in mystery, fantasy, or science fiction.
He was nominated for the Hugo Award for Best Related Work for Transformations: The Story of the Science Fiction Magazines from 1950 to 1970 in 2006.
In addition to the books listed below, Ashley edited and prepared for publication the novel The Enchantresses (1997) by Vera Chapman.
He wrote the books to accompany British Library exhibitions Taking Liberties in 2008 and Out of This World: Science Fiction But Not As You Know It in 2011.