Phase 1 of a four part study was undertaken to investigate the use of scientific and technical information (STI) by U.S. aerospace engineers and scientists. Specific attention was paid to institutional and sociometric variables and to the step-by-step process of information gathering used by the respondents. Data were collected by means of three self-administered mail-back questionnaires. The approximately 34,000 members of the American Institute of Aeronautics and Astronautics served as the study population. More than 65 percent of the randomly selected respondants returned the questionnaires in each of the three groups. Respondants relied more heavily on informal sources of information than formal sources and turned to librarians and other technical information specialists only when they did not obtain results via informal means or their own formal searches. The report includes frequency distributions for the questions. Pinelli, Thomas E. and Kennedy, John M. and White, Terry F. Langley Research Center...