An excellent book. Greene does a very good job of explaining advanced physical theories to the layman. I enjoyed his writing, and the examples used were clear, interesting, and often funny. All of the more advanced mathematics was hidden behind endnotes, many of which could be skipped, if the reader desired.
The book starts with excellent introductions of Einstein’s special and general relativity – by far the best that I’ve ever read. I did find that the content became more advanced as the book continued, and after two-thirds of the way through, I stoped reading the endnotes “for the mathematically inclined”, because I’d hit the level of my inclination. I didn’t find that this reduced my enjoyment of the book any, though.
An excellent book. Read it.