A major 1964 prison study, Glaser (1964), presented about four pages of data and analysis concerning prisoners’ correspondence and visits with family and friends.^ Those pages described the correlation between frequency of a prisoners’ correspondence and visits with family and friends and parole success for four samples of prisoners. The first sample was from Lloyd E. Ohlin’s Ph.D. dissertation at the University of Chicago (1954) (prisoners released from 1925 to 1935), the second from Daniel Glaser’s Ph.D. dissertation at the University of Chicago (1954) (prisoners released from 1940 to 1949), and the third from an unreferenced U.S. Parole Board study of 1954-55 Federal Youth Correction Act commitments (prisoners released from 1954 to 1955). The fourth sample was original to Glaser (1964) (prisoners released in 1956).