Introduction : the thought of the Muslim brotherhood, at the center of orthodox Islam - Finding continuity in an unusual and tumultuous history - The founding of the brotherhood - The contemporary brotherhood - Migration and implantation in Europe - A diverse heritage, marked by a succession of outstanding personalities - The unchallenged foundational contribution of Hassan al-Banna - The thought of Sayyid Qutb : difficult to avoid, but discreetly controversial - Other classic intellectual figures - Historical references from within the movement - Living figures of reference - A dynamic tradition more or less held in check - Ideas that lead to action - Two complementary versions of the movement's heritage - The brotherhood through action - Framework principles for the Muslim community - Morals and social life - Discourses regarding ultimate purposes and the relationships between different civilizations - Concrete political projects? - Strong but confused ideas.