Groundbreaking book about decision making, especially in difficult situations (stress, time, consequences, vague information). Lots of stories and studies about fire fighters, nurses, military commanders, chess grandmasters ... The main point is, that the majority of decisions are not done (for good reasons) in the classically recommended way by evaluating alternatives and making a choice, but by something called "Recognition-Primed Decision" making. This type of decision making is rarely less than 50% and can go up 95% with warship commanders and fire fighters. RPD means that they build on the recognition of familiar patterns from experience (personal, stories, training) and seek solutions one at a time. A solution is put through "mental simulation". If it works, that's it. If not, another solution is tried. Of course I can't summarize the 400 pages in a paragraph. There is much more to it (major chapters about: The RPD Model, Intuition, Mental Simulation, The Power to Spot Leverage Point, The Power to See the Invisible, The Power of Stories, Metaphors and Analogues, The Power to Read Minds, The Power of the Team Mind, The Power of Rational Analysis and the Problem of Hyperrationality, Why Good People [sometimes] make Poor Decisions). It may explain a lot about XP and online communities. An awesome book, highly recommended. -- HelmutLeitner