Angle's chapter, "The Angle system of regulation and retention of teeth," represented the first edition of what was later separately published as Angle's textbook on orthodontics with the same title. This chapter reappeared in the second edition of Haskell's manual (1890). The first separate edition of Angle's work was a revised and enlarged version of what originated as the chapter, issued in 1892. That separate edition was identified as the third edition.