First day cover honoring Paul Dudley White, M.D. postmarked in Washington on September 15, 1986, signed in black felt tip ink by Denton Cooley, dated September 1, 1998. Light waviness, otherwise in very good condition. 

Denton Arthur Cooley (August 22, 1920 – November 18, 2016) was an American cardiothoracic surgeon famous for performing the first implantation of a total artificial heart. Cooley was also the founder and surgeon in-chief of The Texas Heart Institute, chief of Cardiovascular Surgery at clinical partner Baylor St. Luke's Medical Center, consultant in Cardiovascular Surgery at Texas Children's Hospital and a clinical professor of Surgery at McGovern Medical School at the University of Texas Health Science Center at Houston