Mad About Books
Publisher's site includes information, excerpts, promos, and sales of their books as well as event information.
http://www.madaboutbooks.com/

Maple Lane Publishing
Publishing and selling apple, seafood, family cookbooks - and shipwreck books.
http://www.the-westcoaster.com/

McGraw-Hill Bookstore
Professional titles, including computer, business, scientific, architecture, engineering and technical books.
http://www.mhprofessional.com/

Medusa Books
Las Vegas-based publisher and promoter of general interest books.
http://www.medusabooks.com/

Melton Publishing
Independent publisher of books about the American West, the Pacific Northwest, and the outdoors, as well as a Gothic romance.
http://www.meltonpub.com/

Micro Margin
Books sold at discounts.
http://www.micromargin.com/isroot/MicroMargin/info.html

MSP Books
Selection of books from Main Street Publishing.
http://www.mspbooks.com/