Edward Jenner discovered the process of vaccination, when he found that injection with cowpox protected against smallpox. His method of immunization via vaccination ushered in the new science of immunology.

Jenner was born in Berkeley, England, the third son and youngest of six children of Stephen Jenner, a clergyman of the Church of England. He was orphaned at age five and was raised by his older sister, who was married to a clergyman. When Jenner was thirteen years old, he was apprenticed to a surgeon. Then in 1770, he moved to London, England, to work with John Hunter (1728 - 1798), an eminent Scottish anatomist and surgeon who encouraged Jenner to be inquisitive and experimental in his approach to medicine. Jenner returned to Berkeley in 1773, and set up practice as a country doctor.

During and prior to Jenner's lifetime, smallpox was a common and often fatal disease worldwide. Many centuries before...