In the 1960s, aircraft manufacturers began to consider a second generation of jetliners -- one focus being on increasing capacity through "widebody" aircraft configurations. Among the results of this exercise were two three-engine "jumbo jets" -- the McDonnell "Douglas DC-10" (and improved "MD-11"), plus the less successful Lockheed "L-1011 Tristar" -- and the classic "Boeing 747". This document provides a history and description of the DC-10, Tristar, and 747.