Soon users of Columbia University's law library will be able to retrieve texts from computer workstations because the school opted to digitize its collection instead of constructing a new building. And so the digital realm overpowers and redefines our physical environment and, in the process, raises new architectural and urban design issues, claims William Mitchell in the online version of his book City of Bits.

With this interactive site, Mitchell, dean of architecture and planning at M.I.T., certainly redefines our idea of a book: The seven chapters are amply hyperlinked, reviews will be posted on an ongoing basis, and readers are invited to leave comments, to which the author may respond. Mitchell even provides the URLs to hundreds of 'surf sites' that cover subjects from advertising to the World Wide Web. Eventually, however, the book must be read.

Here the site falters somewhat. Mitchell spends a lot of time musing about cyberspace's history and the digital future in overwrought prose, describing a book as 'tree flakes encased in dead cow,' and the Internet as a 'worldwide, time-zone-spanning optic nerve with electronic eyeballs at its endpoints?' In addition, he offers few solid details about the social systems and funds that must be in place for his ruminations on the future to become reality. It's doubtful, for example, that a nation unable to agree on a national health care plan would support homes networked as virtual clinics, replete with diagnostic and monitoring devices.

Mitchell is on firmer ground when he offers suggestions on how virtual and physical public spaces should relate. Citizen access to electronic public sites (such as government agency Web pages and community networks) shouldn't be limited to computers in the home or business, he writes. People need access via civic architecture: the electronic kiosk in the lobby of city hall or in the public library. Here Mitchell is more realistic: he realizes that these electronic networks inevitably will compete with other public works for scarce funds.