Described by The New York Times as "one of the nation's most influential legal librarians", he wrote extensively about the history of law and helped organize and computerize the law libraries at Harvard and Yale.

[1] Cohen was born on November 2, 1927, in The Bronx and attended the New York City Public Schools.

He focused the remainder of his career as a law librarian and professor, and would later describe how he "celebrated my departure from practice as a great emancipation".

[3] He donated his "Juvenile Jurisprudence Collection" to the Yale Law Library in 2009, a collection he had started decades earlier that included early publications related to juvenile law.

[2] A resident of New Haven, Connecticut, Cohen died at the age of 83 of leukemia on December 18, 2010, at his home there.