It is with great pleasure that we are able to provide the reader with a translation of Souriau's elassical text "Structure des Systemes Dy- namiques" on mechanics. We have added the subtitle "a symplectic view of physics", which is elose to the title first proposed by the author. Compared to the French version, we have made several changes in nota- tion for the English edition, all of which have the author's approval. The most important change is...