Various tools for writers operated by the ReAnimus Press crew:

More Issues at Hand, by James Blish (as William Atheling, Jr.)
The Craft of Writing Science Fiction that Sells, by Ben Bova

General:

Specific to Smashwords:

SF in Dimension, by Alexei and Cory Panshin
Heinlein in Dimension, by Alexei Panshin
The Science Fiction Novel, by Basil Davenport, Robert A. Heinlein, C. M. Kornbluth, Alfred Bester, and Robert BlochGalaxy Magazine: The Dark and the Light Years, by David L. RosheimFootprints on Sand, by L. Sprague de Camp and Catherine Crook de CampHeinleinAnthopology 101: Reflections, Inspections and Dissections of SF Anthologies, by Bud WebsterSpace Travel - A Science Fiction WriterHow To Improve Your Speculative Fiction Openings, by Robert QualkinbushHaving Relationships With Characters on the Road to Great Fiction, by Andrew BurtStaying Alive - A WriterThe Issue at Hand, by James Blish (as William Atheling, Jr.)Of Worlds Beyond, by Lloyd Arthur Eshbach, ed.Modern Science Fiction, by Reginald Bretnor, ed.