**Saunders Mac Lane** was an American mathematician who worked in cohomology and category theory, but who is best known for the algebra book he wrote with Garrett Birkhoff.

- When he was only one month old his parents decided they did not like the name Leslie and from that time on he was known as Saunders MacLane.
- The change from MacLane to Mac Lane only came about many years later after his marriage.
- Mac Lane's early years were spent in several different small towns but he did live in one large city, spending a few years in Boston when aged around seven.
- Saunders graduated in 1926 from high school and, in that year, he entered Yale University.
- He offered to provide Mac Lane with sufficient funds to cover his expenses at Yale but he expected Mac Lane to train for a career in either business or law.
- He gave me lots of encouragement and said, "Mac Lane, why don't you take the Barge Prize examination?" They gave that examination to freshmen every year.
- Within weeks he was completely bored by accounting and, after one of his classmates said how much he was enjoying physics, Mac Lane went on to major in both mathematics and physics.
- By this time E H Moore was nearly seventy years old but his advice to Mac Lane to study for a doctorate at Göttingen in Germany certainly persuaded Mac Lane to work at the foremost mathematical research centre in the world at that time.
- Mac Lane began to work for his doctorate under Paul Bernays' supervision but in 1933 the Nazis came to power.
- Mac Lane had seen that he had to work quickly for his doctorate and leave Germany as soon as possible before things deteriorated further.
- Mac Lane was rather disappointed to learn that Weyl had only rated his thesis "sufficient".
- On returning to the United States, Mac Lane spent the session 1933-34 at Yale while he tried to get a university position for the following year.
- The impact of Birkhoff and Mac Lane on the content and teaching of algebra in colleges and universities was immediate and long sustained.
- In 1952, five years after being appointed, Mac Lane took over the chairmanship of the department from Stone who stepped down as chairmen but remained on the staff for another sixteen years.
- Though teaching from his own book, it seemed that Mac Lane would go out of his way to present the material differently than what was in the text.
- However, the understanding of the mathematics was paramount in Mac Lane's presentations.
- Mac Lane's work covered a wide range of mathematics.
- Mac Lane was the author of seven books: (with Garrett Birkhoff) A Survey of Modern Algebra (1941); Homology (1963); (with Garrett Birkhoff) Algebra (1967); Categories for the Working Mathematician (1971); Mathematics, Form and Function (1985); (with Ieke Moerdijk) Sheaves in Geometry and Logic: A First Introduction to Topos Theory (1992); and Saunders Mac Lane: A Mathematical Autobiography (2005).
- For his contributions to the Mathematical Association of America, Mac Lane received the Association's Award for Distinguished Service for 1975.
- Mac Lane's hobbies included skiing, hiking and writing poetry.

Born 4 August 1909, Norwich, Connecticut, USA. Died 14 April 2005, San Francisco, California, USA.

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Bourbaki, Origin Usa

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive