Edward de Bono does not suffer from a small ego. The first sentence of the preface to his book is: "The Six Thinking Hats method may well be the most important change in human thinking for the past twenty-three hundred years." Digest this and two more pages of obnoxious self-advertisement that follows. Then put the book down. After an hour continue to read the rest of the book. It is worth while. Essentially, "Six Thinking Hats" is about improving communication and decision-making in groups. De Bono's style is accessible, succinct, well-structured and easy to follow. It is not with a certain justification that he claims that "his work is in use equally in board-rooms of some of the world's largest corporations and with four-year-olds in school." Well, where is the difference, anyway? What de Bono wants to achieve is to structure thinking and make it more effective. "Thinking often proceeds as drift and waffle and reaction to what turns up from moment to moment. [...] Suggestions, judgements, criticism, information and plain emotions are all mixed together in a sort of thinking stew," he writes. The six "thinking hats" are different ways of looking at an issue that has to be decided: under the white hat one presents the facts, under the red hat one says how one feels about the issue, under the black hat one looks at the negative effects of the decision, under the yellow hat one looks at the positive effects of the decision, under the green hat one thinks of alternatives, and under the blue hat one clarifies which kind of thinking is going on. Overall, thinking becomes clearer when the different parts that go into it are brought into the open. The idea of the "hat" has the advantage that it allows people to play with a new perspective. People who argue by criticism, for example, can remain mostly critical.