"This directory lists the names, and the latest address known to the Laboratory, of (1) personnel actively connected with the Laboratory (consultants as well as employees) on June 1, 1945, (2) employees who hav joined the Laboratory since June 1, 1945, and (3) all research associates who have ever been employed by the Laboratory. ...we have omitted only the names of those few to whom we have addressed first-class mail which has been returend to us by the Post Office stampled 'Moved, left no address.' Personnel Department"--transcribed from title page.