Christian Albert Theodor Billroth (1829-1894), a German-born Austrian surgeon, is generally regarded as the founding father of modern abdominal surgery. Billroth was apprenticed to Carl von Langenbuch and practiced surgery at Vienna, as chief of the Second Surgical Clinic at the Allgemeine Krankenhaus (Vienna General Hospital) and professor of surgery at the University of Vienna.

Billroth was directly responsible for a number of landmarks in surgery, including the first esophagectomy (1871), the first laryngectomy (1873), and most famously, the first successful gastrectomy (1881) for gastric cancer, after many an ill-fated attempt. Legend has it that Billroth was nearly stoned to death in the streets of Vienna when his first gastrectomy patient died after the procedure.

Billroth was also instrumental in establishing the first modern "school of thought" in surgery, and among his disciples were counted luminaries such as Alexander von Winiwarter and Johann von Mikulicz-Radecki . William Halsted 's pioner surgical residency program was greatly influenced by Billroth's own methods of surgical education.

In addition to his impressive contributions to surgery, Theodor Billroth was also a passionate musician, a violin virtuoso and a close friend of Johannes Brahms.