The Year's Best Science Fiction: Twenty-First Annual Collection
| Editor | Gardner Dozois |
|---|---|
| Language | English |
| Series | The Year's Best Science Fiction |
| Genre | Science fiction |
| Publisher | St. Martin's Press |
Publication date | 2004 |
| Publication place | United States |
| Media type | Print (hardback & paperback) |
| Pages | 665 pp |
| ISBN | 9780312324780 (hardcover) ISBN 9780312324797 (trade paperback) |
| OCLC | 55801735 |
| Preceded by | The Year's Best Science Fiction: Twentieth Annual Collection |
| Followed by | The Year's Best Science Fiction: Twenty-Second Annual Collection |
The Year's Best Science Fiction: Twenty-First Annual Collection is a science fiction anthology edited by American writer Gardner Dozois, published in 2004. It is the 21st in The Year's Best Science Fiction series. The anthology was published in the UK as The Mammoth Book of Best New Science Fiction 17.