Among the many factors in the recent development of secondary schools in the United States the following appear to be of special significance and for that reason have been selected for treatment in this article: (1) The numbers of schools and pupils; (2) the reorganization movement which presents the junior high school as its outstanding contribution to education; (3) the growth in junior colleges; (4) the important part played by private secondary schools; (5) the interest in curriculum revision; (6) the articulation of units which offers especial difficulties for secondary schools; (7) the cooperative attack on the problems of secondary education through an extensive survey national in scope. (Contains 4 tables and 24 footnotes.) [Best copy available has been provided.]