Saunders Mac Lane was born in 1909 in San Francisco, California. He was actually the co-founder of the category theory with Samuel Eilenberg. Saunders earned a BA from Yale University in 1930 and a MA from the University of Chicago, while attending the University he published his first paper in the category of physics with Irving Langmuir. After graduation from about 1934 to 1938, he held an appointment at Harvard University, Cornell University and University of Chicago. He then held a brief tenure at Harvard from 1938 to 1947 and after that he spent the rest of his career at the University of Chicago.

Saunders Mac Lane also held the job of Vice President of the National Academy of Sciences and the American Philosophical Society and as President of the Mathematical Association of America in the 1950’s. Mac Lane had a great career but it was his contributions that made him a stand out in the Math community. During his early work he had come up with his thesis in mathematical logic and his early original work was in field theory and valuation theory.

He was the first mathematician to introduce the Eilenberg-Steenrod axiom and an abstract look at homology theory. It was shortly after that he and Eileneberg came up with the collaboration of the category theory in 1945. Mac Lane is also known for his work on what is called coherence theories.

He was also an accomplished writer, he authored such books as A Survey of Modern Algebra in 1997 with Garrett Burkoff and in 1995 he wrote Homology, and in 1999 he coauthored Algebra with Garrett Burkoff. In 2005, A.K Peters wrote a great tell all book called Saunders Mac Lane: A Mathematicians Biography. He was a great man with many great ideas and theories. He is very well known today in the world of mathematicians and he was and still is very well respected.