This circular gives a brief story of the origin and present status of the research associate plan which has recently grown notably both in magnitude and variety of fields. Examples are given of actual cases with a brief account of the research problems. Some published results are listed by title and citation to place of publication. A list of associates with the names of sustaining organizations and the problems under investigation is given. The actions of Congress which authorized the opening up of the Bureau's facilities for study and research are quoted in full. Research in progress ranges from fundamental science to the most practical applications in industry.