"...minus several million for good thinking..."
- Zaphod Beeblebrox, THE HITCHHIKER'S GUIDE TO THE GALAXY
The above quote (and the score I've assigned to this book) aren't in reference to the text or the author, but to the publishers. Why anyone with the brains of a sea urchin would cross Professor Hawking as they seem to have done is beyond me.
Briefly, save your money and buy THE ILLUSTRATED BRIEF HISTORY OF TIME instead of THE THEORY OF EVERYTHING, even if you're a compulsive Hawking completist. Alert readers should notice that Hawking doesn't hold the copyright for THEORY OF EVERYTHING, and attempted to block its publication. It was originally titled THE CAMBRIDGE LECTURES: LIFE WORKS, and appears to have been drawn from some recordings of lectures given by the professor years ago. (See the professor's web site for details.)
The "vanilla" (i.e., not the ILLUSTRATED) THEORY OF EVERYTHING consists of an introduction, seven lectures, and an index, without *any* illustrations or diagrams. Out of curiosity, I compared a library copy of it with THE ILLUSTRATED BRIEF HISTORY OF TIME.
Unless otherwise noted, each of the 7 lectures corresponds to a chapter of the same name in BRIEF HISTORY, in some segments only with slightly different paragraphing and punctuation (and occasionally the kind of spelling errors that creep in when one transcribes audio narration to text, if I may speculate as to the cause).
I don't understand why anyone would prefer the less polished text of THEORY OF EVERYTHING to THE ILLUSTRATED BRIEF HISTORY OF TIME, which not only has updates for new areas of research, but has been revised and rearranged to explain things more gently to the layperson.
"Ideas About the Universe" is essentially an extract from "Our Picture of the Universe", the first chapter of BRIEF HISTORY, with about one sentence's worth of drift per paragraph.
BRIEF HISTORY's version of "The Expanding Universe" has a more gradual introduction to the methods of measuring distances to nearby stars, and explains technical terms that may be unfamiliar to the non-scientist, such as luminosity.
THEORY OF EVERYTHING really shows its age in "Black Holes" when compared to BRIEF HISTORY, as Hawking has not been idle in that area over the years. The illustrated edition of BRIEF HISTORY has had a fair bit of interesting material added to "Black Holes", especially regarding cosmic censorship and naked singularities (Hawking having made a few *more* bets on the subject with Preskill and Thorne, although he paid off the Cygnus X-1 wager).
"Black Holes Ain't So Black" lacks major blocks of clarification/explanation added by Hawking to the version in BRIEF HISTORY.
BRIEF HISTORY's version of "The Origin and Fate of the Universe" goes into more detail: about the kinds of particles that are predicted to have come out of the big bang, and what sort of results we'd expect to see today if the predictions hold, and the scientists who first put forward these theories. BRIEF HISTORY also contains a much longer version of the "open questions" section, leading more gradually up to the discussion of Guth's development of the inflationary model.
"The Direction of Time" corresponds to BRIEF HISTORY's "The Arrow of Time" (which is worth picking up just for the picture of the keeper of the U.S. cesium clock). BRIEF HISTORY goes into more detailed examples to explain what Hawking means by the psychological arrow of time, with the simplest kind of "computer": an abacus.
"The Theory of Everything" mainly corresponds to BRIEF HISTORY's more modestly titled "The Unification of Physics", which is much more up to date (string theories are still covered, but a lot more work has been done in that area over the years). The tail end of the lecture corresponds to the ending of BRIEF HISTORY's "Conclusion".
In summary, this is interesting stuff, but THE ILLUSTRATED BRIEF HISTORY OF TIME does it better.