By understanding its past, a field of study and practice can better understand its present and improve its future, yet the field of educational supervision has done very little to document or contemplate its history. In this paper, 10 books on supervision published from 1920 through 1950 are reviewed, including books by Nutt (1920), Burton (1922), Crabbs (1925), Barr and Burton (1926), Nutt (1928), Kyte (1930), Barr (1931), Rorer (1942), Barr, Burton, and Brueckner (1947), and Wiles (1950). The discussion of each book is organized into three parts. First, the author discusses a concept from the book that he believes should be "retained," meaning the concept should continue to be discussed and acted upon. Second, the author reviews a concept no longer valued or utilized that he argues should be revived in order to improve present-day supervision. Third, the author describes a concept discussed in the book under review that he maintains should be "reproved" as a negative influence on the field. The reader is urged to review historical literature on supervision and form her or his own perspectives on the value of historical concepts to modern supervision.