Michael Walsh is a prolific writer and commentator on the Catholic Church. In this new book he concentrates on the four thousand or so men who donned the red hat and became Princes of the Church, men who were on the whole rich, powerful and influential. They were a colourful lot, some of them scoundrels involved in political and sexual intrigues and not always outstanding in doctrine or piety. Others were scholars and saints. Walsh casts an objectively critical eye on a selection of these who became famous as schemers, politicians, scholars, soldiers or diplomats. They are selected mostly from the Renaissance period, but there are some also from the nineteenth and twentieth centuries. Walsh tells their story dispassionately and critically, sketching the high points of their careers and assessing their contribution to the church they professed to cherish. This is a book of careful scholarship, but also very readable. There were few cardinals who led dull and uninteresting lives.