Gail's Books
Used and rare books in many categories.
http://www.gailsbooks.com/

Garwood & Voigt
Sales catalogue of valuable and rare antique books, maps and prints.
http://www.garwood-voigt.com/

Gibson's Books
Used, rare and out of print books; specializes in children's books, 1st editions, southern authors, and ephemera.
http://www.gibsonbooks.com/

Golden Books Group
UK based leather books and leather bindings specialist; stock includes art, prints, and maps.
http://www.goldenbooksgroup.co.uk

Golden Bough Vintage Books
Specialities include Georgia authors, Georgia and the South; military, especially the Civil War and World War II; religion, and modern first editions.
http://www.goldenbough.com/index.htm

Golden Legend
Rare and fine books and prints, especially on theatrical history, dance, costume and fashion history.
http://www.goldenlegend.com/

Great Books On Main
Old, new, rare and out of print books.
http://www.greatbooks.ca/

Green Apple Books and Music
Searchable site; variety of topics.
http://www.greenapplebooks.com/

Greenfield Books
Old, rare and out of print books.
http://www.greenfieldbooks.com/