Samuel (Sammy) Eilenberg (1913 - 1998) is a Polish mathematician who emigrated in US just before WW2. He obtained his Phd from Warsaw University in 1936 under the supervision of Karol Borsuk?. He spended most of his career at Columbia University. His students include Alex Heller?, David Buchsbaum?, Daniel Kan, William Lawvere, Jonathan Beck, Harry Applegate? and Myles Tierney?.
Sammy Eilenberg is the cofounder of category theory with Saunders Mac Lane, with whom he collaborated on group homology; they introduced Eilenberg-MacLane spaces? in topology. His book Foundation of Algebraic Topology? with Norman Steenrod revolutionised the subject with axiomatic homology theories. His book Homological Algebra? with Henri Cartan opened a new field. He pionneered the applications of category theory to computer science with his book Automata, languages, and machines?.
Eilenberg initiated the North American School of Category Theory with Mac Lane. He was a member of Bourbaki for many years.