A very nice article on the future growth of the CBA market:

Most agree that the category’s growth is noteworthy, and there is no end in sight. In 2009, industry experts expect the religious books segment to account for $2.91 billion, which represents about a 50 percent increase from 2004, Greco added. The category includes Bibles, New Testaments, hymnals and prayer books along with a more nebulous category of "other religious," which accounted for $1.28 billion in 2004, Greco said.

With some comments on the rules of this genre: 

Other religious books encompass thrillers, mysteries, a burgeoning romance category and general fiction, he added. There are no bodice-rippers in the Christian romance market, and many publishers have a list of taboo subjects that include premarital sex, bad language and homosexuality, said industry members.

Read more: DenverPost.com