The USAF Statistical Digest summarizes the great volume of statistical information collected and published by the various offices in Headquarters, and certain USAF commands. The more important data on the many activities and operations of the USAF are brought together on a uniform basis to serve as an official and basic reference manual. The Jan 1949 - Jun 1950 "USAF Statistical Digest" is the fifth edition of the publication series. Original editions - Army Air Force Statistical Digest (World War II) and Supplement Number 1, 1945 were followed by AAF Statistical Digest 1946 and USAF Statistical Digest 1947. The present issue includes the majority of the tables carried in the earlier volumes with the exception of the section on World War II combat operations. Historical continuity has been preserved, and each series has been brought forward through 1946. Continuing research in the sources and validity of the data has, in several instances, effected major changes and extended the data to cover earlier periods. Several revisions, both in content and format, have been made during the preparation of this issue. For example, the many reorganizations and regroupings of commands preclude the continuity in any series on personnel information by command. To overcome the changes in command structure, a new box head has been introduced at the appropriate date. By this device, reorganization changes become more readily apparent. Where a command has merely undergone a change in name as in the case of Air Materiel Command - from Air Technical Service Command - the newest name is utilized generally throughout the series.