William Halsted was an influential American surgeon born in 1852. He is best known for his pioneering work in surgical techniques and his role in establishing the modern practice of surgery. Halsted introduced the concept of using anesthesia in surgery and developed the Halsted mastectomy, a procedure for breast cancer treatment. Halsted also contributed to the development of the sterile technique, which greatly reduced the risk of infection during surgeries. He was a key figure at Johns Hopkins Hospital, where he served as the first chief of surgery. His innovations laid the groundwork for many surgical practices used today.