Books that discuss the nature of reality have become a cottage industry lately. Brian Greene, Stephen Hawking, Roger Penrose and now Max Tegmark have all attempted to explain the physicist's view of the ultimate nature of reality to a popular audience. Penrose's book, with its advanced mathematics, is geared towards those with a technical background but the trend has been to simplify the science and make these books anecdotal and gentle. Tegmark seems to have discovered the sweet spot between hard core science and a fun read, using the word "geeky" as a red flag any time a technical detail is about to be broached. His language is reader friendly and easy to understand. Tegmark is a good writer and anyone that has seen him on television (Through the Wormhole, for example) knows that he is funny and well-grounded in popular culture. Our Mathematical Universe is a nearly perfect example of a popularized science book.
Years of reading science books have produced a personal pantheon of the finest I've ever come across. There are several aspects of Tegmark's book that have placed it amongst the three finest popular science books I've ever read. The other two books are Albert Einstein and Leopold Infield's The Evolution of Physics and Kip Thorne's Black Holes and Time Warps: Einstein's Outrageous Legacy (Commonwealth Fund Book Program). The first book, The Evolution of Physics, is still the clearest exposition of classical and (relatively) modern physics ever written, despite its age. It remains the most authoritative, concise and profound discussion of the source of Einstein's world-shattering ideas, and has never been surpassed as a book written by a great scientist for a popular audience. Kip Thorne's book combines personal reminiscence and scientific exposition with an elegance and depth that makes it my choice as the finest modern popularized science book. Thorne proved that you can write about science in an engaging manner without sacrificing either intelligence or necessary relevant technical detail.
The attributes that raise Tegmark's book amongst the very finest in the genre are its engaging writing style, its willingness to discuss technical details about recent trends in cosmology without sacrificing either intelligence or clarity, and its almost subversive depth. Tegmark has a flair for discussing some really knotty topics like the significance of the cosmic microwave background, Einstein's theory of gravitation, the geometry of curved space, mathematically precise cosmology, dark matter and dark energy without losing the reader in a labyrinth of confusing and difficult scientific details. Tegmark teaches without ever being pedantic and he entertains while he clarifies and enlightens. There aren't many science writers who can write about such abstract and craggy subjects as cosmology, multiple multiverse levels, and mathematics as the ultimate nature of physical reality with Tegmark's wit and ease. If you are a fan of reading popularized science books, Our Mathematical Universe is one of the finest I've ever read and definitely worth your consideration.