In the age opened by the Second Vatican Council and marked by the epochal stocktaking of its history and perspectives that the Catholic Church initiated with the great Jubilee of the Year 2000, the Council of Trent appears at the same time close and remote. On the one hand, it recalls the age of the wars of religion; on the other, with its solemn reaffirmation of Catholic identity, it appears as the starting point of a consolidation and renewal of the Church, an essential premise of subsequent developments. The book aims to offer a guide to introduce the main aspects of the Council and its work.