What is a dangerous idea? One not assumed to be false, but possibly true?What do you believe is true even though you cannot prove it?" These are the questions of the last two years that Edge Foundation asked of 120 free thinkers. The audacious and stimulating answers have been reproduced by in hundreds of newspapers such as The New York Times or Frankfurter Allgemeine Zeitung. Among the hundreds of ideas are the demonstration of life in other planets, or that life has been a unique chance of existing; concerns over the fact that there are genetic differences relating to intelligence between ethnic groups and between the sexes; the inference that global warming is not so worrisome, the notion that there are alternatives to the free market.