The Danish physician and anatomist Thomas Bartholin (1616-1680) was one of the most diligent communicators of scientific knowledge of his time. He is famous for his discovery and naming of the lymph vessels, for his editions of Europe's most widely used anatomy book in the 17th century and for being the founder and editor of the world's first medical journal. Bartholin published more than 80 books. Most of them were about anatomy and medicine, but he also wrote about unicorns, comets and light emitted by living organisms. His extensive correspondence with physicians and scholars constitutes a scientific and cultural treasure. As professor of anatomy and medicine for more than 30 years and dean of the medical faculty, Bartholin was the main force behind the flourishing of medical studies at the University of Copenhagen. He was a teacher and inspirer of the anatomist, geologist and theologian Niels Stensen (1638-1686) and crucial to Stensen's groundbreaking scientific career. This first biography of Thomas Bartholin in English presents his life and achievements through primary sources.