In what little Copious Free Time I have left, I've been slowly reading yet another book about quantum field theory. I may be being overly optimistic, but it feels like it's almost starting to make sense (or at least to make as much sense as quantum theories ever do*). I'm not sure whether this particular book is more comprehensible, or whether it's just that I've now looked at enough different books to begin to get a coherent understanding.
I think part of the problem is that almost all of the books are written from the perspective of a physicist rather than a mathematician. They tend to assume you're intimately familiar with Maxwell electromagnetism and spin, rather than concentrating on the mathematical structures. (This is actually in contrast to most of the presentations of relativity, both special and general, which tend to be more axiomatic and mathematically satisfying). I've often been tempted by the 'Quantum Field Theory for Mathematicians' book on these grounds, but given that I've got more QFT books than I'm ever likely to read (er, 5) and given that it's £85, I'll stick with the ones I've got and hope to make sense of them eventually.
Anyway, I hope this isn't a false dawn and that I may soon come to understand what's going on down below the turtles.
*One of my favourite chunks from this book is '..it is fair to say that the conceptual basis of the theory is still somewhat obscure. I myself do not properly understand what it is that quantum theory tells us about the nature of the physical world, and by saying this I mean to imply that I do not think anyone else understands it either'. Penrose's most recent magnum opus also has a whole chapter on the unresolved conceptual problems of quantum theory.