The standards set in teacher-certification requirements, and the effectiveness of the administration of certification, have been intimately related to the advancement of public education. The major portions of previous reports from the Office of Education were devoted to the presentation of the detailed requirements for obtaining the different kinds of certificates issued in the several States; of the regulations governing their scope of validity, duration, and similar items; and of certain tendencies prevailing at the time the publications were issued. During the past decade certification requirements and practices have been changing with great rapidity, and numerous differences that have prevailed for many years in the certification standards of the States have intensified. The present study was undertaken to bring together from the literature on teacher certification such principles, authoritative proposal, and suggestions for improved practice as appear to be of value to certification officers, research workers, public-school and college officers and teachers, and laymen interested in improving certification practices and requirements. To assist in the realization of this purpose, the present status of certification practice is given in respect to selected items in which important differences exist among States, and in which desirable changes may be brought about. Trends are shown which appear to indicate the directions in which future changes may be expected to occur. It is believed that such materials may be of service to those who construct or influence the construction of State programs of teacher certification. Includes an extensive bibliography. (Contains 19 footnotes and 12 tables.) [Best copy available has been provided.]