His writing style is beautifully simple and the content is therefore easy for anyone to read and understand.
Some parts of the first edition are available online:
HN, what does "Whether it decays or not depends upon properties of that system that have been smoothed away by the quantum wave" mean?! What properties exactly, and smoothed away how? Just by the fact that observing the system causes a change within the system and therefore changes the quantum waves?
This statement you quote has often been called by the jargon name "hidden variables theory". You're asking: What are these hidden variables? Well, Einstein could never find them, and later work has shown that this is because they don't exist. Read the end of the chapter first. ;)
Incidentally, at first glance this chapter doesn't look like light reading.
Here is an example of a non-local hidden variable theory: http://en.wikipedia.org/wiki/Bohm_interpretation
To say that properties "have been smoothed away" means that the particular statistical measures that quantum theory was using were losing the fine-grained detail necessary for understanding particular events. It's not that the "quantum wave" is literally smoothing things in the world, but that the theory of the "quantum wave" is disregarding particular facts.
Imagine that we described human populations without having the ability to observe individual sex characteristics, or individual human interactions. We might say things like "a human has a 10% chance of splitting into two humans over the course of a 20 year span." In this case, our statistics "smooth away" differences such as sex, and the interactions of specific humans over time, leaving us with a probabilistic statement. We might start reading the apparent non-determinism as a fact of nature, rather than as a problem with our knowledge.
He put forth this theory before the EPR experiments (he's the E); these experiments made that interpretation unlikely. Specifically, the EPR experiments showed that the state (if any) is probably non-local.
I'm looking for the tersest complete guide from Newtonian physics to GR. Single author would be best, but I imagine it's not possible.
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I'm not quite sure, though, if tel was asking for full mathematical developments of the theory (in which case the combo of MTW and Wald are, IMO, indisputable must haves), or something that just gets to the point quickly, assuming that you don't need help on the math.
In any case, anyone and everyone should also read Penrose's Road To Reality (my own shameless affiliate link: http://amzn.com/0679776311?tag=gubbins-20) for a very different take on...well, pretty much everything. The book is a complete failure at its stated goal of making mathematical physics accessible for a lay audience (I suspect when you're as smart as Penrose it's hard to figure out what an average Joe is capable of grokking...), but as a casual and wildly different sweep through a lot of interesting topics for someone that already knows math, it's fantastic.