The "USAF Statistical Digest" (Short Title USAFSD-55) summarizes in one document the volume of statistical data collected and published by various offices in Headquarters, United States Air Force and certain major commands. It is to be used as the official basic reference document for the period and areas covered. The Fiscal Year 1955 edition is the tenth edition of the 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 1946 and 1947 editions made Air Force statistics available.in summarized form, available as far back as possible, with the exception of Combat Operations. This data is found only in the 1945 edition. The 1948 issue was the first strictly annual publication. The present issue and the 1949, 1950, 1951, 1952, 1953 and 1954 editions are organized on a Fiscal Year basis. Immediately following the Table of Contents is a Major Air Command Directory, containing information which is appropriate to all data included in this issue. Definitions appropriate to only one area will be found in an introductory statement preceding the Part in question. Tables indicated in the headnote as "New Tables" are tables which were not included in the FY 54 edition of this publication.