There is a full-length biography of Kurt Godel by John Dawson, one of Godel's literary executors and a co-editor of his collected works. In the meantime, this short book tries to give the non-mathenmatician a basic grounding in the facts of his life, the nature of his achievement and the measure of his continuing influence. It's true that the non-technical explanations of Godel's work are remarkably ingenious and vivid, but in most cases they weren't necessarily invented by the book's authors. The style is often awkward, reading as though it was translated from the German by somebody for whom English isn't a first language, and there are a number of basic factual errors - for example, Ludwig Wittgenstein never wrote a book called "Logical Investigations". Being the biography fiend that I am, I could have done with a lot more about Godel's bizarre life and eccentric personality, but maybe it's best to appreciate the man's work before we start being curious about, for example, why he thought he was being poisoned.
To conclude: approach this little sucker with caution. It seems overpriced to me, and the mistakes I've noticed only make me worry about the ones that I haven't.