This landmark study examined whether high-volume hospitals have better outcomes for major cardiovascular and oncologic surgery. The study found that patients undergoing major surgery in high-volume hospitals have significantly lower risk-adjusted mortality compared to other hospitals. However, there is wide variation in the difference in mortality across procedures. The chapter describes the basics of the study, including funding, year study began, year study was published, study location, who was studied, who was excluded, how many patients, study design, study intervention, follow-up, endpoints, results, and criticism and limitations. The chapter briefly reviews other relevant studies and information, gives a summary and discusses implications, and concludes with a relevant clinical case.