British surgeon who, inspired by Pasteur's germ theory, introduced antiseptic surgical technique in 1865 using carbolic acid (phenol) to sterilise wounds, instruments, and the surgeon's hands. Before Lister, post-operative infection ('ward fever') killed 40–50% of surgical patients. His systematic application of antisepsis cut mortality to under 15% and transformed surgery from a last resort into a routine medical intervention. He is regarded as the father of modern surgery.

• Nationality: british
• Roles: surgeon, scientist