S & L New and Used Books  
   Used books of all types in numerous categories with thumbnails.
   http://members.tripod.com/essell/Books%20-%20Main%20Page.htm

Scrinium Classical Antiquity  
   Secondhand and antiquarian books on classical antiquity. Online catalogues available.
   http://www.scrinium.nl/

Sean Fagan, Rare Books  
   Book seller offering a searchable database and photographed catalogs of scarce books in many fields.
   http://www.faganbooks.com/

Second Life Books  
   Antiquarian and out of print books by and about women, first editions of literature, agriculture, and horticulture; a range of printed and manuscript material from the 16th to the 20th century.
   http://www.secondlifebooks.com/

Signed Rare Books  
   Signed rare books, modern first editions and antique books.
   http://www.signedrarebooks.com/

Sheila Markham Rare Books  
   The East; exotic printing, calligraphy and general antiquarian books.
   http://www.sheila-markham.com/sheila_markham.html

Sleepygirl's Used Books  
   An internet only used bookstore.
   http://www.sleepygirlsusedbooks.com/

Sigler Press  
   Out-of-print books about Biblical studies, theology, church history, and pastoral care.
   http://www.siglerpress.com/

Skriptoriet Used Books  
   Scandinavian used and antiquarian books and online entry of book location requests. Bilingual, Swedish and English.
   http://www.skriptoriet.se/

Sumner and Stillman  
   Antiquarian Booksellers, specializing in nineteenth century British, Irish and American literary first editions.
   http://www.sumnerandstillman.com/

Sheringham Books  
   Sells fiction, while linked Whirlwind books sells non-fiction.
   http://www.sheringham.co.uk/acatalog/

Steve the Fish  
   One man business selling first editions and collectable books.
   http://www.stevethefish.co.uk/

Second Story Books  
   Used books; Mystery and Science Fiction catalogues issued regularly.
   http://www.secondstorybooks.com/

Simpson Books  
   Specializing in modern, out-of print, first edition collectable books, many signed by the author.
   http://simpsonbooks.com/

Serendipity Books  
   Used, rare and out of print books. Specializing in nonfiction including science, history, religion, and social sciences; based in Michigan.
   http://www.serendipitybooksinmichigan.com/

Sagarin Vintage Books  
   Used, secondhand and out of print books; free book search, and book appraisal.
   http://www.members.aol.com/hagpress/sag.htm

Sangraal Books  
   Used books, in browsable categories, including fiction, philosophy and fantasy.
   http://sangraal-books.com/

SeekBooks.co.uk  
   Used and hard to find books; browsable and searchable site.
   http://www.seekbooks.co.uk/

Savoy Books  
   Specializing in horticulture and agriculture, historical Americana, English and American literature.
   http://www.vgernet.net/frakerbook/

Slightly Read Books  
   General stock open bookstore in Grinnell, Iowa. Searchable, browsable site.
   http://www.slightlyreadbooks.com/

Sassy's Hide - A - Way  
   Many categories of books including; mystery, romance, children's, educational, and novels.
   http://www.geocities.com/sassyshideaway/

Stone House Books  
   Specializes in modern first editions, collectible children, science fiction, horror, mystery and Edgar Rice Burroughs "Tarzan" books.
   http://www.stonehousebooks.com/

Sage Old Books  
   Modern first editions, author signed books, Australiana, plus wide range of 19th and 20th century used books.
   http://www.sageold.com.au/index.shtml

Symposion Books  
   Auction hall and online antiquariat.
   http://www.symposionbooks.com/

Signed Books  
   A collection of new books that have been signed by the authors.
   http://www.signed-books.co.uk/

Seasoned Books  
   Specializing in books on sustainable lifestyles, wilderness adventures and renewable energies.
   http://www.seasonedbooks.com/

Straight Arrow Publications  
   Used, rare books, and first editions. Includes reviews and links, specializing in historical matters; also has Native American genealogy.
   http://members.aol.com/fa11leaf/

Schwartz Judaica  
   Out-of-print books of Jewish interest from art to Zionism, in various languages, including English, Hebrew, Yiddish, and German.
   http://www.schwartzjudaica.com/

Studio Bibliografico san Mamolo  
   Specializes in old and used books about nature, science and history. Also in Italian.
   http://www.diecidieci.com/mamolo_new/

Significant Books  
   General books, also with a specialist interest in science and technology.
   http://www.significantbooks.com/

Sunbow Books  
   Used books searchable by author, title or keyword.
   http://www.tomfolio.com/mall/sunbowbooks/

Stackstreet Books  
   Rare literature, first editions, poetry, science-fiction, graphics, New Zealand.
   http://www.abebooks.com/home/STACKST9/

SS Enterprise Books  
   Includes archaeology, history, fiction, military, and royalty.
   http://ssenterprise.tripod.com/books.htm