For those unfamiliar, John Baez is great. One of the few people who seems to have a good, highly connected understanding across most/all of modern physics. This is very rare even among physicists. He's also credited in a lot of excellent ([hard] science fiction) books by Greg Egan.
John is fantastic, not only a nice person with absolutely zero ego, he has brain and heart and he has such a deep love for science, a funny writer too. Anything that he writes (TWIMP,his diary,his blog Azimuth, n-category cafe, his book ) is highly recommended.
This is a must read for the aspiring mathematician or physicist:
