The Mammoth Book series •
The Mammoth Book of Steampunk (2012) •
The Mammoth Book of Steampunk Adventures (2014) •
The Mammoth Book of Warriors and Wizardry (2014) •
The Mammoth Book of Dieselpunk (2015) •
The Mammoth Book of Kaiju (2016)
The Realms/Clarkesworld series •
Realms: The First Year of Clarkesworld Magazine (2008), with Neil Clarke and Nick Mamatas •
Realms: The Second Year of Clarkesworld Magazine (2010), with Neil Clarke and Nick Mamatas •
Clarkesworld: Year Three (2013), with Neil Clarke and Nick Mamatas •
Clarkesworld: Year Four (2013), with Neil Clarke •
Clarkesworld: Year Five (2013), with Neil Clarke •
Clarkesworld: Year Six (2014), with Neil Clarke •
Clarkesworld: Year Seven (2015), with Neil Clarke •
Clarkesworld: Year Eight (2016), with Neil Clarke •
Clarkesworld: Year Nine, Volume One (2018), with Neil Clarke •
Clarkesworld: Year Nine, Volume Two (2018), with Neil Clarke •
Clarkesworld: Year Ten, Volume One (2019), with Neil Clarke •
Clarkesworld: Year Ten, Volume Two (2019), with Neil Clarke •
Clarkesworld: Year Eleven, Volume One (2019), with Neil Clarke •
Clarkesworld: Year Eleven, Volume Two (2019), with Neil Clarke •
Clarkesworld: Year Twelve, Volume One (2021), with Neil Clarke •
Clarkesworld: Year Twelve, Volume Two (2021), with Neil Clarke
Other anthologies •
Bandersnatch (2007), with Paul Tremblay •
Best New Fantasy (2006) •
Fantasy (2007), with Paul Tremblay •
Fantasy Annual 3 (1999), with Philip J. Harbottle •
Fantasy Annual 4 (2000), with Philip J. Harbottle •
Fantasy Annual 5 (2003), with Philip J. Harbottle •
Horror: The Best of the Year (2006), with John Betancourt •
Japanese Dreams (2009) •
People of the Book: A Decade of Jewish Science Fiction and Fantasy (2011), with Rachel Swirsky •
Phantom (2009), with Paul Tremblay •
Robots: Recent A.I. (2012), with Rich Horton •
Strange Pleasures (2006) •
War & Space: Recent Combat (2012), with Rich Horton •
Weird Tales: The Twenty-First Century (2007), with Stephen H. Segal
Other works •
Eric Frank Russell: Our Sentinel in Space : A Working Bibliography: 3rd Revised Edition (1999), with Phil Stephensen-Payne •
The Tall Adventurer: The Works of E.C. Tubb (1997), with Philip J. Harbottle •
The SFWA Bulletin Index, 1965-2017 (2018), with Michael Capobianco and Erin M. Hartshorn •
The Graphic Novels / Manga / Comic Strips / Comics Master List, Grades K through 5 (2019-), with Jennifer Wallace
Magazines edited •
Il Buio (Italian edition of
The Dark), with Silvia Moreno-Garcia and Lorenzo Crescentini (September 2018 – 2019); 7 issues, along with an omnibus,
Il Buio, Anno 1 (2019) •
Clarkesworld Magazine, with Nick Mamatas (October 2006-July 2008); with Neil Clarke (August 2008-current); 220 issues •
The Dark Magazine, with Jack Fisher (October 2013-April 2016), 11 issues; solely (May 2016-December 2016), 8 issues; with Silvia Moreno-Garcia (January 2017-December 2020), 48 issues; solely (January 2021-June 2022), 18 issues; with Clara Madrigano, (July 2022-June 2023), 12 issues; solely (July 2022-January 2025): total: 116 issues •
Fantasy Magazine (2005); with Paul Tremblay (2006-2007); with
Cat Rambo (2007-2011); 47 issues •
Podcastle (November 2009), guest editor; 1 issue •
Thaumatrope (August 2009), guest editor; 1 issue •
Underworlds: The Magazine of Noir and Dark Suspense (2004); 1 issue
Journals edited •
Fantasy Annual, with Philip J. Harbottle (1997-1998), 2 volumes •
Jabberwocky (2006-2007), 3 issues; with Erzebet YellowBoy (2009-2011), 6 issues ==Essays and articles==