Various tools for writers operated by the ReAnimus Press crew:

The Issue at Hand, by James Blish (as William Atheling, Jr.)
More Issues at Hand, by James Blish (as William Atheling, Jr.)

General:

Specific to Smashwords:

Having Relationships With Characters on the Road to Great Fiction, by Andrew Burt
In Search of Wonder, by Damon Knight
Staying Alive - A WriterThe Craft of Writing Science Fiction that Sells, by Ben BovaHow To Improve Your Speculative Fiction Openings, by Robert QualkinbushAnthopology 101: Reflections, Inspections and Dissections of SF Anthologies, by Bud WebsterOf Worlds Beyond, by Lloyd Arthur Eshbach, ed.Space Travel - A Science Fiction WriterMagic of Wild Places, by Bruce TaylorRage of Stars: Book Three of The Sigil Trilogy, by Henry GeeTimeshare, by Joshua DannThe Haploids, by Jerry SohlA Song of Awakening, by Roby JamesCosmic Coincidences, by John Gribbin and Martin Rees