Even if the world needed a book on this theme, this is not the one!
One thread of this book is the notion of collision between scientific thinking and theology--a collision which in my view is not forced by anything observable or reasonably thinkable.
In early chapters, the author makes dogmatic statements about what was on the minds of numerous famous authors--statements for which no justification is given, and for thoughts which arguably have milder and more flattering interpretations: e.g., that Dante and other mediaevals took a certain spatial view of heaven and hell literally. In this case, the milder interpretation might recognize that writing anything likely to offend certain Churchmen risked persecution--so that what authors expressed might often left out subtle and careful thinking.
The chapters on what's going on since the mid-1980's read like a journalist's hasty pastiche of things written and thought by others, with little acknowledgement and even less discernable new thought.
However, my main objection is that this author has set up a flimsy strawman to knock down with many words, viz., that the coincidence of the syllable "space" in "cyberspace" implies a serious analogy to metric spaces. This analogy might play a roll in hoi poloi minds, but that Wertheim's middle chapters talk of the work of several well-known scientists seems to imply that serious scientists take such an analogy seriously. In many years of listening to scientific colleagues, I heard nothing to suggest such a view.
In contrast, Wertheim ignores all social thinking that is a reasonable precursor to today's views and actions around cyberspace. Recall the notion that "a university is a community centered on a library", and many, many related works about how communities work and about domains of ideas.
Furthermore, in discussing science Wertheim ignores the most important factor that drove philosophical and scientific thinkers to their views of metric spaces--symmetry and simple forms in differential equations.
On the positive side, I learned a few obscure and very interesting names--those of thinkers before their time. E.g., Nicolas of Cusa (13th century), Kaluza (19th century). I'll dig into those.
Summary: for any careful thinker, this book is a distraction and waste of time.