Sacred Spaces
Selection of books and products related to a group of authors.
http://www.sacredspaces.org/

Sam Weller's Zion Bookstore
New, used and rare titles. Includes a newsletter and regional picks.
http://www.samwellers.com/

Sands Publishing
Fiction and nonfiction books in most genres, including general, suspense, romance, mystery, sci-fi, children's, spiritual, and memoirs.
http://sandspublishing.com

Sapna
Showroom for books located in Bangalore - India.
http://www.sapnaonline.com/

Savage Press
Selection of books on a variety of subjects.
http://www.savpress.com/

Schiffer Books
Titles on antiques and collectibles, military collectibles and history.
http://www.schifferbooks.com/

Seaview Press
Self-published books, mostly from Australia and around the world. Includes details of the self-publishing process.
http://www.seaviewpress.com.au/

SeekBooks Australia
Large catalog by subject.
http://www.seekbooks.com.au/

Self Help Guides
Easy to use, and professionally written guides on many topics.
http://www.selfhelpguides.com/

Shakespeare and Company
Online bookstore selling books in all categories.
http://www.shakeandco.com

Sidney T. Black Publishing, Inc.
Fiction and non-fiction by political activist David Truskoff. Includes biographical information about author.
http://users.erols.com/suttonbear/

Siso Books
Publishers of books related to religious, epics, computer, tales, dictionaries, grammar, classics; both in English and Malalyalam languages.
http://www.sisobooks.net/

Sleeping Bear Press
Golf, children's, turfgrass management, health and nature.
http://www.sleepingbearpress.com/

Sociosights Press
Featuring 'Katherine Stinson: The Flying Schoolgirl,' a biography of an aviatrix.
http://www.sociosights.com/

Stackpole Books
Publishing books on fly fishing, nature, outdoor sports, crafts and hobbies, history, civil war, and military reference since 1927.
http://www.stackpolebooks.com/

Student Book World
New textbooks in categories - or search.
http://www.studentbookworld.com/

Substance Books
Links book sales to authors.
http://www.substancebooks.com/

Sunstone Press
General interest books as well as non-fiction books featuring the American Southwest.
http://www.sunstonepress.com

Swot Books
Textbooks and general list from the UK for students and academics.
http://www.swotbooks.com/