Michael Servetus (c.1506-1553), denounced by many of his contemporaries as an arch-heretic and celebrated by others as a martyr for the cause of religious freedom, escaped from imprisonment by the Inquisition in France, only to be convicted of heresy and blasphemy by the Swiss Protestants and executed by being burned at the stake. The sequence of events leading to Servetus's death began with his publication of a theological work he had long been composing in secret, The Restoration of Christianity.

Though the book was so thoroughly suppressed that only three copies survived, handwritten copies of one three-page passage began to circulate in the seventeenth century. For as part of his depiction of the activity of the Holy Spirit, Servetus - a medical doctor as well as a theologian - presented new and ground- breaking anatomical and physiological information. Seventy-five years before William Harvey presented his description of the circulation of the blood, Servetus became the first European to publish an accurate description of the path of the blood through the heart and lungs.

This book, the third volume in a series, contains an annotated translation of book 5 of The Restoration of Christianity, which includes the famous passage on the pulmonary transit. Two appendixes discuss how Servetus did and did not differ from the medical orthodoxy of his day, and explore his place in the history of medicine.

But Servetus's contribution to medical science is only a small part of this book. Just as revolutionary is his vision of a universe in which everything partakes of the substance of God, and human beings have the potential to become divine.