For the purpose of this bulletin, extension classes are defined as classes organized to meet the needs of persons who are not resident students of an educational institution. Four kinds of extension classes may be distinguished--ordinary classes, short-course classes, lecture classes, and group or club study classes. This grouping is somewhat artificial, and is intended primarily for convenience in presentation, but it is also based upon differences of character which are real. The contents of this bulletin include the following: (1) Preface; (2) Definition of extension teaching; (3) Ordinary classes; (4) The short course; (5) Lecture courses; (6) Club study classes; (7) Number of class centers; (8) Number of extension classes conducted; (9) The subjects taught; (10) Conditions of admission to extension classes; (11) Previous educational training of class extension students; (12) Age of students; (13) Sex distribution; (14) Fees for class extension work; (15) Use of fees; (16) Methods of preventing conflict in the class extension work of a State; (17) The State board of control; (18) The extension commission; (19) Institutional administration of class extension work; (20) Extension administrative centers; (21) Local class extension associations; (22) District divisions without distinct administrative organization; (23) Field organizers; (24) Local organization of extension classes; (25) Administration of extension classes on the campus; (26) Qualifications of instructors; (27) Meetings; (28) Length of class extension courses; (29) Books and equipment; (30) Examinations; (31) Credit for class extension work; (32) Credit toward higher degrees; (33) Transfer of credits; (34) Extension scholarships; (35) Students served in extension classes; and (36) Conclusion. (Contains 3 footnotes.) [Best copy available has been provided.]