IT'S called the Wayback Machine, and as far as the Internet is concerned, that's what it allows a seeker of information to do -- go way back, to the dawn of the World Wide Web, to the tune of billions of Web pages of online information, and at no charge.

Wayback, at www.archive.org, is the brainchild of Brewster Kahle, 42, a computer scientist responsible for a number of Internet search systems, including the Thinking Machines nationwide computerized library; the Wide Area Information Server, an information retrieval system for the Internet; and, with Bruce Gilliat, Alexa Internet, a search engine built into a browser that was sold to Amazon.com a few years ago.

''The opportunity of our generation is to make the library accessible to everyone and live in a very different world,'' said Mr. Kahle (pronounced kale). He was inspired to create the Wayback Machine when he visited the offices of Alta Vista in Palo Alto, Calif., and was struck by the enormity of the task being undertaken and achieved: to store and index everything that was on the Web. ''I was standing there, looking at this machine that was the size of five or six Coke machines, and there was an 'aha moment' that said, 'You can do everything.' ''

In 1996, Mr. Kahle, with Mr. Gilliat, developed the software to download Web sites.

Every two months, the Wayback Machine downloads and stores every Web page it can put its virtual hands on -- that is, every public Web page on every public Web site. Excluded are sites that require a fee for access or sites that Web masters have asked not to be stored.

Last October, after collecting 10 billion Web pages, the Wayback Machine opened its doors to all. The archive contains 100 terabytes -- or a hundred-trillion bytes -- of data. The Library of Congress has a quarter of that amount.

The Wayback Machine is financed on a budget of $10 million a year by several foundations, trusts and corporations, including the Kahle/Austin Foundation, the National Science Foundation, the Library of Congress and the Markle Foundation.

Mr. Kahle also has a whimsical side. The Wayback Machine is named for the time machine used by the pedantic dog, Mr. Peabody, and his boy, Sherman, from the ''Rocky and Bullwinkle'' cartoons.

But Mr. Kahle said the one-liner he finds most compelling is from Raj Reddy, a professor of computer science at Carnegie Mellon University: ''Universal access to human knowledge is within our grasp.''

That, Mr. Kahle said, is ''a pulse-quickening goal.'' JUDY TONG

Photos: Brewster Kahle's Wayback Machine, a Web archive, is named after the cartoon time machine of Mr. Peabody and Sherman.