Religio Medici by Sir Thomas Browne.

At age thirty, Sir Thomas Browne wrote Religio Medici, an explanation and analysis of his religious belief in relationship to his profession as a medical doctor. Intended as a personal meditation, Religio Medici circulated in manuscript form for several years, spawning various unauthorized texts. When a critical response to it was published, Browne saw to the publication of a new, authorized edition. Both documents, appearing during an era of social and religious upheaval when men could be executed for expressing their religious beliefs, present a tactful, idiosyncratic expression of a spiritual life shaped by Christian doctrine, medieval and classical thinking, and the explosion of knowledge occurring in the seventeenth century.