The once-dreaded scourge of smallpox has been eradicated through barrier immunisation. The eminent scientist Edward Jenner (1749-1823) was a pioneer in demonstrating that vaccination was an effective means of preventing smallpox. In the three groundbreaking treatises contained in this volume, originally published between 1798 and 1800, Jenner summarises his evidence in favour of vaccination and describes individual cases.Smallpox was responsible for an estimated 300–500 million deaths during the 20th century alone.[10][11][12] In the early 1950s an estimated 50 million cases of smallpox occurred in the world each year.[13] As recently as 1967, the World Health Organization (WHO) estimated that 15 million people contracted the disease and that two million died in that year.[13] After successful vaccination campaigns throughout the 19th and 20th centuries, the WHO certified the eradication of smallpox in December 1979.[13] To this day, smallpox is the only human infectious disease to have been eradicated