This document is a comprehensive report on a large-scale research project to develop and validate a computerized selection battery to hire Air Traffic Control Specialists (ATCSs) for the Federal Aviation Administration (FAA). The purpose of this report is to document the validity of the Air Traffic Selection and Training (AT-SAT) battery according to legal and professional guidelines. An overview of the project is provided, followed by a history of the various job analyses efforts. Development of predictors and criterion measures are given in detail. The document concludes with the presentation of the validation of predictors and analyses of archival data.