As The First Randomized Controlled Trial (rct) In Criminology And One Of The Earliest Rcts Of A Social Program, The Cambridge-somerville Youth Study (csys) Represents A Landmark Study In The History Of Criminology. The Twin Goals Of The Csys Were, First, To Evaluate The Effects Of A Delinquency Prevention Intervention, And, Second, To Investigate The Development Of Delinquency And Later Criminal Offending Over The Life-course. To Achieve These Objectives, A Renowned Physician And Professor Of Clinical Medicine And Social Ethics At Harvard University, Dr. Richard C. Cabot, Developed A Novel And Highly Rigorous Research Design: A Matched-pair Randomized Controlled Trial With An Embedded Prospective Longitudinal Survey, Known Today As A Longitudinal-experimental Study. Six Hundred Fifty Boys (later Reduced To 506), From Cambridge And Somerville, Massachusetts, Were Enrolled In The Study. Described As Character Development Through Mentoring, The Prevention Intervention Officially Started On June 1, 1939, And Ran Until December 31, 1945. Several Follow-ups, Including Into Middle Age By Joan Mccord, Indicated That The Intervention Did Not Benefit, And May Have Even Harmed, The Treatment Group Boys. The Present Book Provides A Comprehensive Historical Understanding Of The Making Of The Csys. This Includes A Focus On The Study's Development, Operation, And Long-term Follow-up By Joan Mccord And Others. Central To The Book's Approach Is To Place The Histories Of Medicine And The Social Sciences In Direct Conversation With One Another. Richard Cabot Lived At The Interface Of Medicine And The Social Sciences, And The Csys Is A Product Of This Experience-- Provided By Publisher.