From the way this volume is marketed, you could be forgiven for thinking that you are buying a collection of the best short fiction written in the field of science fiction over the past 20 years. Beware, this book does not contain the best of the best over the past twenty years. It does not even contain the best stories from The Year's Best Science Fiction from the past twenty years. On the other hand, it does contain some excellent stories (e.g. A Cabin On the Coast-Gene Wolfe, Salvador-Lucius Shepard, Dinner In Audoghast-Bruce Sterling, The Pure Product-John Kessel, Recording Angel-Ian MacDonald, and others.) But it also contains inexcusably slight and, in some instances, downright unreadable stories (e.g. Trinity -Nancy Kress, execrable chick-lit of the worst kind, The Winter Market-William Gibson, pretentious, narcissistic drool, Coming of Age In Karhide-Ursula K. Le Guin, if I want to read the gory details about puberty I'll stick to medical manuals which at least deal with humans, Lobsters-Charles Stross, twenty pages of supercool, pseudo-hightech gibberish that will make you look forward to your next root canal.) Another problem, when Dozois does get the author right, he often gets the story wrong. (e.g. He chose the slight, silly Even the Queen-Connie Willis, when he could have chosen Cibola or Last of the Winnebagoes. He chose the good but excruciatingly slow Story of Your Life-Ted Chiang, instead of the brilliant, exotic Tower of Babylon, while Salvador-Lucius Shepard is a good story, A Spanish Lesson and The Ends of the Earth are much better. Tales From the Venia Woods-Robert Silverberg is also a good story but pales beside A Long Night's Vigil In the Temple and Sailing to Byzantium -so what if it's a bit long, it's a true classic, None So Blind-Joe Haldeman is okay, Graves would have been a much better choice, etc.) And why would Dozois feel he should limit his best authors to just one story in the volume? If this is supposed to be the best of the best why not put in two Silverberg or three Shepard stories instead of including piffle like Bears Discover Fire-Terry Bisson? And why no George R.R. Martin, one of the top five short story writers over the past thirty years? Under Siege belonged in this volume. Why no Gregory Benford? Of Space/Time and the River belonged in this volume. Alphas belonged in this volume. Why no John Varley? Press Enter belonged in this volume. If this is supposed to be the best science fiction in the past twenty years, why isn't the profoundly disturbing The Angel of Violence-Adam Wisniewski-Snerg included? So, while I think this is a good collection of stories, it should have been a great collection of stories, but isn't.