To help fill that gap, Safari Books Online offers its "Rough Cuts" service, where subscribers can pay to read technology how-to books on the Web as they are written chapter by chapter. Subscribers can also offer comments to the author, such as suggesting the inclusion of more details or other changes before the final book is printed.

"We're trying to leverage the power of the Internet" to give IT workers early access to books in progress and get their feedback to make the works as accurate and topical as possible, said Sean Devine, president of Sebastopol, Calif.-based Safari.

The online service, which began in January, allows subscribers to purchase access for about 50% of the cost of the print book. Safari, a joint venture between O'Reilly Media Inc. and The Pearson Technology Group, has been selling electronic versions of its tech books for about five years, but this is its first interactive offering. The books can be read online using a Web browser or saved to be read later. Safari has about 1 million user subscriptions for its online books, and around 50,000 have access to the Rough Cuts service, Devine said.

Rough Cuts users can purchase the finished books at a discount after they're published.

One user of the service, Allie Rogers, chief technology officer at software vendor Triple Point Technologies in Westport, Conn., said Rough Cuts has been a boon to him, particularly in getting the freshest information on a regular basis about the still-developing Ruby on Rails scripting language. The book he's reading online, The Ruby Cookbook, won't be published in print until July, but Rogers said he has been able to use it productively through his Rough Cuts subscription, which cost him US$24.99, half of the print edition's expected price of $49.99. His company is using Ruby for internal systems to develop its software products, he said.