Written at the time of the advent of democracy and public opinion in the world, "crowd psychology" is an extraordinarily well-written book that can be read and reread as it is rich and dense. The sentences slamming like slogans, ideas are dazzling, even if sometimes they are a bit faster. The subject is put in historical perspective. Decades before the advent of Hitlerism, Le Bon had prévut that he who can understand and speak to the crowds can be the master. There are very few sociological work of this level or such originality. This is by far the best of all the books written by Gustave Le Bon. Although the tone of the book is not very positive and cheerful, he has a side 'black'. Le Bon was under no illusions about human nature. It shows how the crowds are naive, impressionable, manipulated. It is the opposite of the famous collective intelligence. And then there was the writing style of Gustave Le Bon, his extraordinary way with words, sounds sense of brevity and synthesis. A constantly reissued book in many languages for more than a century, a book that has remained REFERENCE on the subject, a seminal work that first married psychology and sociology and who made discover new horizons thought.