Forrester predicts strong sales for custom-printed trade books and digitized textbooks, which will force publishers to dramatically restructure their processes and technologies. Digital delivery of custom-printed books, textbooks, and eBooks will account for revenues of $7.8 billion -- 17.5 percent of publishing industry revenues -- in five years. Of this amount, only $251 million will come from eBooks, according to Forrester's report "Books Unbound." Taken together, custom printing, digital textbooks, and eBooks will pressure publishers to offer greater consumer choice, variable presentation and delivery, and new ways to purchase, none of which authors can do themselves. The result is a new publishing model that Forrester calls multichannel publishing. Successful publishers will manage all of their content from a single, comprehensive storehouse, a repository containing modular book content and structure. According to Forrester's report, multichannel publishers will develop current business practices to match the Internet's speed and convenience. For example, negotiations between publishers' editors and authors' agents must begin to incorporate online research, communities of interest, Net promotional plans, and product variants. Multichannel publishing requires acquisitions driven by identification of demand, maximum flexibility in product packaging, and improved time to market. To realize the benefits of digital books, Forrester says multichannel publishers will need new technologies that support multichannel delivery. Successful companies will adopt XML to separate content from layout and enable delivery on any platform or device. Publishers will also convert content into both PDF and OpeneBook (OeB) files, which are easier than XML to repurpose and share with partners. Digital books will also change the book marketing industry, which has long been a matter of co-op bookseller ads, author appearances, and word of mouth -- all geared toward driving store traffic. In the case of digital books, however, Forrester says every promotional message is also an opportunity to buy on the spot, and the product itself doesn't exist until it is delivered to the buyer. Flexible pricing and value-added components further reinforce successful multichannel publishing. For its report, Forrester interviewed 51 trade, educational, and professional publishers and surveyed 71 authors via e-mail. Each publish an average of 430 new books per year and typically have an active backlist of 1,486 titles.