Here are the stories that David Hartwell and I selected for inclusion in the Year's Best SF 12. They are listed alphabetically by author, rather than in the order that they appear in the table of contents:

“The Lowland Expedition” by Stephen Baxter
“Applied Mathematical Theology” by Gregory Benford
“Brother, Can you Spare a Dime” by Terry Bisson
“Silence in Florence” by Ian Creasey
“When Sysadmins Ruled the Earth” by Cory Doctorow
“Counterfactual” by Gardner R. Dozois
“Quill” by Carol Emshwiller
“Dawn, and Sunset, and the Colours of the Earth” by Michael Flynn
“Damascus” by Darryl Gregory
“Speak, Geek” by Eileen Gunn
“Expedition, With Recipes” by Joe Haldeman
“The Women of Our Occupation” by Kameron Hurley
“Nano Comes to Clifford Falls” by Nancy Kress
“This Is the Ice Age” by Claude Lalumière
“Just Do It” by Heather Lindsley
“Taking Good Care of Myself” by Ian R. MacLeod
“Dead Men Walking” by Paul J. McAuley
“Heisenberg Elementary” by Wil McCarthy
“Rwanda” by Robert Reed
“Tiger Burning” by Alastair Reynolds
“Home Movies” by Mary Rosenblum
“Preemption” by Charlie Rosenkrantz
“Chu and the Nants” by Rudy Rucker
“Tin Marsh” by Michael Swanwick
“Moon Does Run” by Edd Vick
“The Age of Ice” by Liz Williams