When you think “book club,” you may think of old biddies, crumpets, Aquanet, doilies, and a mystery novel. Or you may think of that blasted “O” sticker you spent ten minutes peeling off your copy of 100 Years of Solitude. But the mail-order book club is a different beast altogether, supplying titles of interest to niche markets since the early twentieth century and–despite the advent of the mega-bookstore and Amazon.com–still kicking today.

This week brings news that Bertelsmann AG of Germany will acquire the other 50% of Bookspan from Time, Inc. The two companies joined forces in 2000, when Time’s Book-of-the-Month Club and Bertelsmann’s Doubleday Book Club combined to create Bookspan, which now operates over 35 book clubs. According to the Wall Street Journal, Bertelsmann (owner of Random House, the world’s biggest publisher) bought Time’s share of Bookspan for $150 million and will incorporate it into its BMG Columbia House, which currently runs the Columbia House music and DVD clubs it purchased in 2005.

Even if you aren’t familiar with Bookspan, you’re probably familiar with its modus operandi: An irresistible initial offer (”Ten books for ten cents!”) is followed by a required commitment to order a particular amount of items over a particular span of time. Customers can choose from a catalog of deeply discounted, specialized titles that are shipped to them on a regular basis, and unless they opt out, the books keep coming. If you don’t tell them what you want, they’ll just send you something and hope you like it. Discounts vary, but can be impressive, some knocking almost 80% off cover price. Other discounts can be beaten by retailers like Amazon.com or even Wal-Mart. In this case, book clubs rely on the convenience of a preselected pool of similar titles to retain customers.

Although a significant portion of Bookspan’s offerings consists of cheaper editions of already-popular books, many of its subsidiary book clubs–the more specialized ones–actively seek to acquire new material of interest to their readership. This can be a nice opportunity for authors to gain exposure and credibility. Don’t expect to make much money: Book clubs generally offer around 10% of the book club cover price, which may in turn be only 70% of regular retail price. If, however, your book is accepted into a book club, you get wide exposure to your target audience, as well as the ability to market your book as a “book club pick.” Brian Jud warns in Beyond the Bookstore to avoid making a hasty offer when negotiating with a book club; instead, ask them for standard terms and go from there. Follow these instructions when submitting a manuscript to a Bookspan club, and always submit at least six months in advance of your publication date.

It’s also helpful to check out other titles in the catalog of the club you’re considering submitting to. See if you fit in. Another helpful tip from Brian Jud: based on what you see in the catalog, draft some copy that you think would best sell your book to members.

Here are some examples of special-interest Bookspan clubs. For a full list, click here.

History Book Club: Choose from a selection of books relating to all things history, from ancient to WWII.

Equestrian’s Edge: Books of all types for horse enthusiasts, including fiction, instructional books, and horse history.

American Compass: Offers a catalog suited to today’s conservative reader. Hot titles are from names like Bill “Culture Warrior” O’Reilly, Sean Hannity, and Ann Coulter.

InsightOut: Books for LGBT readers on a variety of topics.

One Spirit: A one-stop shop for books on yoga, spirituality, nature, and, of course, the Law of Attraction.