Jonathan Mock Beck (1935-2006) was a category theorist whose thesis (under the supervision of Sammy Eilenberg) and subsequent work with Mike Barr have been highly influential in the development of the subject.
Jonathan M. Beck: Triples, algebras and cohomology, PhD thesis, Columbia University (1967), reprinted as: Reprints in Theory and Applications of Categories 2 (2003) 1-59 [tac:tr2, pdf]