This book contains all of Leonardo Da Vinci's drawings on the heart and its physiology, accompanied by re-translations of all of the associated notes. All Leonardo's drawings have been interpreted in the light of modern knowledge by a practicing cardiac clinician and anatomist. The veracity of his work is proven against contemporary dissections of cardiac structure and comparison of his illustrations with contemporary images generated by Magnetic Resonance scanners and high definition ultrasound will astound the reader. Perhaps the most interesting element is the re-dissection of the Ox heart set against Leonardo's own drawings. His place in the greater scheme of anatomical development will be put into context with his ideas of man's place in the microcosm/macrocosm continuum.