Various tools for writers operated by the ReAnimus Press crew:

Galaxy Magazine: The Dark and the Light Years, by David L. Rosheim
Space Travel - A Science Fiction Writer

General:

Specific to Smashwords:

Modern Science Fiction, by Reginald Bretnor, ed.
Heinlein
Of Worlds Beyond, by Lloyd Arthur Eshbach, ed.Footprints on Sand, by L. Sprague de Camp and Catherine Crook de CampMore Issues at Hand, by James Blish (as William Atheling, Jr.)How To Improve Your Speculative Fiction Openings, by Robert QualkinbushThe Craft of Writing Science Fiction that Sells, by Ben BovaStaying Alive - A WriterThe Issue at Hand, by James Blish (as William Atheling, Jr.)The Science Fiction Novel, by Basil Davenport, Robert A. Heinlein, C. M. Kornbluth, Alfred Bester, and Robert BlochHeinlein in Dimension, by Alexei PanshinAnthopology 101: Reflections, Inspections and Dissections of SF Anthologies, by Bud WebsterSF in Dimension, by Alexei and Cory PanshinHaving Relationships With Characters on the Road to Great Fiction, by Andrew Burt