The aim of this study was to review and analyze all of the "concurrent surgery" (CS) and "overlapping surgery" (OS) literature with the goal of: standardizing terminology, defining discrepancies in the literature and proposing solutions for the current challenges of regulating surgery to achieve maximal safety and efficiency. The CS and OS literature has grown exponentially over the past two years. Before this, there were no significant publications addressing this topic. There is an extremely wide variance on how "running two rooms" is defined and whether it should be permitted. These differences affect our patients' perception of this practice. The literature lacks any comprehensive review of the topic and terminology. We performed a PubMed search to identify studies that considered the issue of OS. The terms "overlapping surgery", "concurrent surgery", and "simultaneous surgery" (SS) were used in the query. We then analyzed the publications identified. The literature contained 18 published studies analyzing OS safety between November 2016 and June 2018. Eight were neurosurgical studies, three were orthopedic, and the remaining seven articles were in other surgical specialties. A total of 1,207,155 surgical cases (range 250->500,000 patients) were analyzed among the 18 studies. There were 57,880 (5.04%) OS cases. The OS rates in the individual studies ranged from 1.2 to 68 per cent (Table 1). Neurosurgical studies had the highest average OS rate of 54 per cent (range 37-68%), whereas the average OS rate in orthopedic surgery was 43 per cent (range 2.7-68%). Approximately one-third of the studies were multicenter investigations (27.7%). The studies measured more than 20 distinct outcomes, but there were only five outcomes that were included in the majority of the studies: mortality rates, reoperation rates, procedure length of time, readmission rates, and hospital length of stay. The current body of literature repeatedly demonstrates that OS is a safe and effective option when undertaken by experienced surgeons who practice it frequently. For successful OS, the Mandatory Attending Portion for two surgeries must not overlap and Unnecessary Anesthesia Time must be prohibited. Hospitals and surgical specialty organizations must implement policies to assure the safe practice of OS.