Wired on Friday/Carol Power: Information technology is, by its very nature, constantly changing. For most computer programmers and IT professionals, this means they are in a continual learning mode in order to improve or enhance their skills to be ready for the next "hot" technology that comes along.

One of the most common ways for IT pros to brush up on new technologies is through the purchase of new and revised technical textbooks. And these books don't come cheap.

Some best-selling technical books at the moment include: Java Cookbook by Ian Darwin which costs €51.60 in Ireland and $44.95 in the US; Java and XML, second edition by Brett McLoughlin, which costs €80.16 in Ireland and $44.95 in the US; Enterprise Java Beans, third edition by Richard Monson-Haefel, which costs €46.01 in Ireland and $44.95 in the US.

My husband, a computer programmer, estimates he has spent a few hundred dollars in the past few years buying books related to .NET, Microsoft's newest technology for developing Web and desktop applications.

Seeing that there may be a niche for people who want to view only the chapters relevant to them instead of buying the whole printed book, two well-known IT publishers, O'Reilly & Associates and the Pearson Technology Group, set up a firm called Safari Books Online LLC in July 2001 to provide programmers and IT professionals with electronic access to the full text of print books in an online, searchable format.

The publishers recognised that programmers were turning to intranets, message boards, colleagues and the Web to find quick answers.

By creating an e-reference library at www.safaribookshelf.com, Pearson and O'Reilly could offer their readers the same content they got in print but in a format that served the need for a quick answer.

So far, the site has exceeded the owners' expectations.

Safari has tens of thousands of individual paid subscribers through its business to consumer portals (such as O'Reilly at http://safari.oreilly.com and Pearson's InformIT (http://safari.informit.com).

From 2002 to 2003, the number of individual subscribers doubled.

Safari has about 400 paid corporate accounts worldwide, which range in size from small work groups and departmental subscriptions to enterprise-wide contracts with as many as 40,000 users in an account.

Safari has contracts with more than 400 academic libraries worldwide.

Nearly 40 per cent of its business-to-consumer subscriber base lies outside the US. After the United States, Safari's biggest population of users reside in the UK, followed by Canada, Australia and Germany.

According to Lynn Little, vice-president of marketing at Safari, based in Boston, Massachusetts: "A great part of Safari's success stems from the fact that Safari is primarily a quick reference tool while a book is primarily used as a learning tool. That is not to say that users never use Safari to learn, or that readers never use a book to look up a quick answer but, on the whole, users look to e-reference libraries and print books to meet different needs."

For example, at the Safari site, a programmer trying to recall a particular Perl parameter can search across thousands of books to pinpoint in seconds the exact book, chapter and section with the answer.

The site also offers programmers the ability to filter searches by code-fragment only and this is a popular feature.

While there are similar services in the academic and corporate worlds, Safari is the only service that provides access to electronic versions of recently published books from O'Reilly and Pearson.

According to Nielsen Bookscan, for the year to date through November 2003, O'Reilly and Pearson published on average four times more top 10 best-sellers in the IT/programming area than its competitors.

Since Safari's launch, the firm has expanded from one service (Safari Tech Books Online) to six services, including Safari Business Books Online, Safari HelpDesk Online and Safari Enterprise Library, a combination of technical, business and desktop application books geared specifically to the large enterprise.

It is now incorporating content from non-owner publishers such as Microsoft Press, Thomson South-Western Books and Thomson Crisp Learning.

When it comes to feedback from the software development community, Ms Little said it had been "overwhelmingly positive".

She added: "Users comment on the quick reference nature of Safari - the fact that they can search across an entire library of books at once. They also like that the information is reliable and portable so they don't have to lug the print book to a client site or from home to work."