I have read innumerable books and science magazine articles on quantum theory, relativity, astrophysics, astrononmy, string theory, etc, as well as a great deal of more generally related science.
I am not a trained scientist, simple a well informed non-specialist with an interest in these areas, and I would have to say that this is the best written book of its type I have come across. It deals with extremely deep concepts across an enormous range of different but related areas of study, and I found myself at times almost shocked at the superb skill with which the author is able to deliver new concepts and arguments so cleanly and simply. The chapter that deals with quantum theory and the many-worlds hypothesis alone stands out as a masterpiece of elegance and simplicity when compared with many other works that attempt to deal with this issue.
Rather than delighting and wallowing in the apparent paradoxes that quantum theory implies for the macroscopic world (as so many authors do), Deutsch simply points out that irrespective of our inability to understand and resolve those paradoxes, the conclusions at least are clear and unarguable, and this is where he starts the real work of philosophical integration that is the books theme.
The rate at which new ideas in this book are delivered can leave one stunned at times, and I must recommend this book without any hesitation at all.