In this the twenty-fifth edition of his celebrated annual Mammoth Book of Best New SF, award-winning editor Gardner Dozois presents most outstanding pieces of short science fiction from 2011, along with his typically informative notes on each author. Many are the work of award-winning writers, but there are also some surprising newcomers. The collection is prefaced, as ever, by Dozois's Summation of 2011 in SF, a review of the year's highlights in publishing and film - including non-fiction, media and awards - obituaries and an insightful look at emerging trends.