The Internet may seem an unlikely gateway for the soul but, as Margaret Wertheim argues in this imaginative book, cyberspace has in recent years become a repository for immense spiritual yearning. The perfect realm awaits, we are told, not behind the pearly gates but behind electronic gateways labeled ".com" and ".net.". Seeking to understand this mapping of spiritual desire onto digitized space, Wertheim takes us on an astonishing historical journey, tracing the evolution of our conception of space from the Middle Ages to today. Beginning with the cosmology of Dante, we see how the medievals saw themselves embedded in both physical space and spiritual space. With the rise of modern science, however, space came to be seen in purely physical terms - with spiritual space written out of the realm of reality. Within this context, Wertheim suggests that cyberspace returns us to an almost medieval position: Once again we have a physical space for body and an immaterial space that many people hope will be a new space for soul. By linking the science of space to the wider cultural and religious milieu, Wertheim shows that the spiritualizing of cyberspace fits into a long history of imagined spaces. In particular, it may be seen as an attempt to realize a technological version of the Christian space of heaven.