This document summarizes the history and development of American football from its origins in the late 19th century to the present. It discusses how the sport grew enormously in popularity in the early 20th century but also faced criticism due to its violence and injuries. It then outlines the current concerns about long-term health issues in former players like chronic traumatic encephalopathy (CTE) and painkiller abuse, which some argue could threaten the future of the sport. The document concludes by noting the NFL's acknowledgement of head injuries and its settlement of a related lawsuit.