THIS IS THE FIRST PORTION OF A THREE-PART REPORT ON THE USE OF CASE STUDIES TO EXAMINE IMPLEMENTATION OF FEDERAL LEGISLATION. IN THIS, THE HISTORICAL BACKGROUND PORTION OF THE REPORT, THE DEVELOPMENT OF THE CASE STUDY TECHNIQUE, IS TRACED FROM THE SIMPLE DESCRIPTIVE STUDIES OF THE 1920'S AND 1930'S TO THE MORE ANALYTICAL STUDIES OF THE 1960'S. IN THE LATE 1960'S STUDIES BEGAN TO DO MORE THAN DESCRIBE. THEY ALSO BEGAN TO TRACE CHANGE OR EXAMINE THE RESULTS OF ACTIVE INTERVENTION. THESE LONGITUDINAL AND IMPLEMENTATION STUDIES HAVE CHANGED RESEARCHERS' PERCEPTION OF THE PLACE OF THE CASE STUDY IN AN EVALUATION. THE METHODOLOGY BEHIND THESE TECHNIQUES IS REVIEWED AND THE USE OF SUCH STUDIES TO EVALUATE MANPOWER PROGRAMS AND EDUCATIONAL PROGRAMS IS DESCRIBED. A STUDY BY THE VERA INSTITUTE OF JUSTICE WHICH EXAMINED THE EFFECT OF CRIMINAL JUSTICE AGENCY ACTIONS ON JAIL OVERCROWDING IS USED AS AN EXAMPLE OF A CASE STUDY SHOWING LINKAGES BETWEEN ACTIONS--STUDIES CALLED 'ITINERARIES' AND 'ORGANIZATIONAL LEARNING.' THIS TYPE OF STUDY IS EXAMINED IN DETAIL. A SCHEMA FOR CASE STUDIES ON IMPLEMENTATION OF FEDERAL LEGISLATION CONSIDERS THREE LEVELS: FEDERAL, STATE, AND LOCAL. SUGGESTIONS FOR USING CASE STUDIES AS PART OF A RESEARCH DESIGN ARE MADE, CONCERNING QUANTIFICATION AS A RESEARCH METHOD, QUALITATIVE WORK PRECEDING SURVEYS, CASE STUDIES USAGE SUBSEQUENT TO STATISTICAL SURVEY ANALYSIS, AND IMPLEMENTATION RESEARCH AS PROCESS ANALYSIS. FOOTNOTES CONTAIN REFERENCES. (GLR)