To understand the philosophy of free and more concretely what happens in the field, this book is a real reference. Beyond the aspect of "free", it is a model of the new work being proposed (collaborative). There is a history of the movement of the free, the advantages and disadvantages, the conditions of a successful open-source project, the different business models of free (the interest for SMEs, companies) and other matters as well interesting. Some parts are technical. Do not hesitate to zap. A book to recommend for those who want to better understand the world of the free.