The opposition of science and religion is a recent phenomenon; in the middle ages, and indeed until the middle of the nineteenth century, there was almost no conflict. In the Middle Ages the objective study of nature - the activity we now call science - was largely the province of religious men. This book looks at the origins of western science and the central role played by the Dominican and Franciscan friars. It explains why these two groups devoted so much intellectual effort to the study of physical and biological phenomena, and distinguishes 'Natural Philosophy' from 'science' as presently understood. Though the friars were recognisably 'scientific' in their approach their motives were religious - they wished to understand the mind of God and the beauty of God's nature. Even so, as this study makes clear, the roots of western science lie in the monasteries and refuges of the medieval friars - the direct forebears of the anti-scientific Popes of the age of Copernicus and Galileo.