Manuscript notes showing measurements, figures and notes on the design of the ball and cage valves including ball to opening ratio, ball size, and availability of materials. 1960 April 1 The M. Lowell Edwards Public History Project was made possible by a grant from the Edwards Lifesciences Fund. We are grateful to Teresa Edwards Allen and the extended family of M. Lowell Edwards for their generosity in sharing documents from the estate of M. Lowell Edwards. We also thank Richard J. Mullins, M.D. for his many contributions to this project.