Hiding in the Mirror by Lawrence Krauss

Lawrence Krauss presents a broad vision of extra dimensions, both from appearances in popular culture to its role in some of our most cutting edge modern theoretical physics, such as string theory. In the end, it's unclear whether or note extra dimensions exist, but it is clear that they have captured the minds of humanity for some time.

In Hiding in the Mirror, astrophysicist and cosmologist Lawrence M. Krauss addresses the concept of extra dimensions, from its appearance in popular culture such as Alice in Wonderland and The Time Machine to theoretical physics areas such as the theory of relativity and string theory. In fact, I would say that the book splits roughly 50/50 between cultural and scientific topics, which is part of the point of the book (that extra dimensions are tied to both areas), but for those who are specifically interested in the scientific aspects there are other books (such as Lisa Randall's Warped Passages) which address the scientific aspects in far more depth.

According to Krauss, extra dimensions have captured the human imagination well before it entered into exploration by physics in the last century or so. The book covers how the concepts were viewed by those in the past, as well as more recent science fiction, such as Star Trek (one of Krauss' favorite topics, as author of the bestselling The Physics of Star Trek). Much of this material is entertaining, but for those who are wanting to get to the heart of the physics, it can feel like filler.

About 100 pages of the book focuses on the recent work to find a unified theory of quantum gravity, focusing predominantly on string theory (with some mention of predecessors). This has been one of the areas where extra dimensions have become extremely dominant. Though Krauss exhibits some genuine skepticism about the track string theory is on, I think calling the book a criticism of string theory would be going a bit far. Krauss is placing string theory within a larger framework of extra dimensional movements in the past, many of which have proved incredibly enlightening and some of which have not done much. It's left to other books to determine whether string theory has any scientific merit.