This book offers a description of the evolution of cams and their uses from the Middle Ages to the present day, highlighting their contribution to the development of technology. Usually, in the history of technology the diverse types of machines are taken into account, but the importance of cams is not emphasized, which are often fundamental for the operation of such machines. In this book the focus is instead on cams, understood as important, and often essential, components of machines that have had significant importance in the development of technology. It treats technical aspects at a level easily accessible even to non-experts in mechanics and the various applications are illustrated with many figures. The book serves as a reference work for those interested in both the history of technology and machines in general, and it helps them deal with certain mechanical problems, even starting from solutions already obtained with cams and, perhaps, overcoming them with others suggested by current developments in technology.