William Harvey's On the Motion of the Heart and Blood in Animals is a classic work of the scientific revolution and of modern medicine, for in it he famously argued, with extensive evidence based on dissections and vivisections, for the circulation of the blood. It also overturned the longstanding theories of the heart's movement and function. This new edition is suitable for classroom use and for general interest. In addition to an updated translation, it also contains an introductory essay and footnotes.