This is an objective and thorough history and presentation of theoretical physics and was well worth the month or so it took me to read from cover to cover. If you are tired of fad physics, annoyed by being sold on pet theories, or the promise that a complete understanding of the universe is just around the corner then you will appreciate the honest and rational treatment that Penrose presents.<br><br>Caveat Emptor -- This is not for tourists. If it's been a while since you've done serious math (or never) -- brush up! (or get comfortable with not understanding the details)  While the first third covers a lot of the relevant math before getting to the fun physics, it is not a math tutorial and the rest of the book assumes you get it.<br><br>Now, I just wish I could find an equally thorough and objective treatment of life sciences ...