service of anyone on the staff. He served with the Seaforth Highlanders in France, as Lieutenant (1914), then as Captain of the 10th Battalion (1915–18). While a Captain in the Fourth Field Survey Battalion of the Royal Engineers in France, he devised sound-ranging equipment to locate enemy artillery. He returned to Princeton after the war, becoming Associate Professor in 1921 and editing the Annals of Mathematics until 1928. While at Princeton, he supervised only three PhDs, one of them being Nathan Jacobson. In his later years, Wedderburn became an increasingly solitary figure and may even have suffered from depression. His isolation after his 1945 early retirement was such that his death from a heart attack was not noticed for several days. His Nachlass was destroyed, as per his instructions. Wedderburn received the MacDougall-Brisbane Gold Medal and Prize from the Royal Society of Edinburgh in 1921, and was elected to the Royal Society of London in 1933. Work In all, Wedderburn published about 40 books and papers, making important advances in the theory of rings, algebras and matrix theory. In 1905, Wedderburn published a paper that included three claimed proofs of a theorem stating that a noncommutative finite division ring could not exist. The proofs all made clever use of the interplay between the additive group of a finite division algebra A, and the multiplicative group A* = A-{0}. Parshall (1983) notes that the first of these three proofs had a gap not noticed at the time. Meanwhile, Wedderburn's Chicago colleague Dickson also found a proof of this result but, believing Wedderburn's first proof to be correct, Dickson acknowledged Wedderburn's priority. But Dickson also noted that Wedderburn constructed his second and third proofs only after having seen Dickson's proof. Parshall concludes that Dickson should be credited with the first correct proof. This theorem yields insights into the structure of finite projective geometries. In their paper on "Non-Desarguesian and non-Pascalian geometries" in the 1907 Transactions of the American Mathematical Society, Wedderburn and Veblen showed that in these geometries, Pascal's theorem is a consequence of Desargues' theorem. They also constructed finite projective geometries which are neither "Desarguesian" nor "Pascalian" (the terminology is Hilbert's). Wedderburn's best-known paper was his sole-authored "On hypercomplex numbers," published in the 1907 Proceedings of the London Mathematical Society, and for which he was awarded the D.Sc. the following year. This paper gives a complete classification of simple and semisimple