Presented is the first of three reports by the National Science Foundation (NSF) on the 1974 National Survey of Scientists and Engineers conducted by the Bureau of Census. The survey was designed to measure the changes, every two years, in the demographic, educational, and employment characteristics of the scientists and engineers identified in the 1970 Census of Population. This report presents detailed information on the 1974 National Sample with emphasis on the demographic and educational characteristics. Almost 1,100,000 scientists and engineers were represented by this National Sample. The publication is divided into two sections: (1) graphic highlights, and (2) selected characteristics. Technical notes, detailed statistical tables, and a reproduction of the 1974 questionnaire and reference lists are included in the appendix. (Author/EB)