Died: 15 September 1978 in Edinburgh, Scotland

William Guthrie's father was the Rev W A Guthrie, D.D., who was the Minister at Fountainbridge Church, Edinburgh, but at the time William was born he was headmaster of Foulford school in Cowdenbeath, Fife. William attended Broughton Secondary School, Edinburgh, completing his school education in 1922 when he was dux of the school. He won the Bruce Bursary to study at the University of Edinburgh. On 21 July 1926 he graduated with an M.A. with First Class Honours in Mathematics and Natural Philosophy. He then followed the route of many Scottish students of this period and, after completing a degree in Scotland, went to Cambridge and effectively took a second 'first degree'. He studied the Mathematical Tripos and became a wrangler (first class student) in 1929.

After graduating from Cambridge, Guthrie was appointed as an Assistant in Mathematics at the University of St Andrews. While teaching at St Andrews he undertook research for his doctorate which was awarded in 1932. In 1933 he was appointed Professor of Mathematics and Natural Philosophy at Magee University College, Londonderry. In addition to this post he was appointed he was elected Bursar of Faculty in 1945, then Principal in October 1958.

It was widely expected that Magee College would become the second university in Northern Ireland when a committee was set up to report. However the committee proposed that the second university be established at Coleraine rather than Londonderry and Guthrie resigned from Magee College on 30 September 1968, the day before the new University of Ulster opened at Coleraine.

Guthrie was a Fellow of the Royal Astronomical Society, a member of the Irish Astronomical Society, and of the Edinburgh Astronomical Society. He was a member of the Edinburgh Mathematical Society, joining in December 1926. He was elected to the Royal Society of Edinburgh on 6 March 1933, his proposers being Herbert Stanley Allen, Herbert Westren Turnbull, David Jack, Edward Thomas Copson.

An obituary, written by H A Brück, appears in the Royal Society of Edinburgh Year Book 1979, pages 35-36. 

Guthrie married Thelma Pate. The announcement of their engagement reads:-

1. H A Brück, William Gilmour Guthrie M.A. (Edin. and Cantab.), Ph.D. (St Andrews), Royal Society of Edinburgh Year Book 1979, 35-36.