OSA Fellow William Edgar Knowles Middleton was born on 23 June 1902 in Wasall, United Kingdom. He moved to Canada in 1911. He received a B.Sc. degree from the University of Saskatchewan in 1927 and an M.Sc., also from the University of Saskatchewan, in 1929. From 1929 to 1946, he worked for the Meteorological Service of Canada where he specialized on measurement and instrumentation including Canada's first automatic weather station. From 1946 to 1963, he was a Research Officer at the National Research Council in Ottawa in the optics branch of the Division of Physics where he specialized in colorimetry. He also taught a course for many years on meteorological instruments at the University of Toronto.

From 1967-1978, after his retirement, Middleton moved to Vancouver, British Columbia, where he was a professor emeritus and honorary lecturer associated with the Department of the History of Medicine and Science at the University of British Columbia.

Middleton wrote 15 books and more than 75 scientific papers related to the science of weather instruments and meteorological optics as well as their history. His major contribution was the book Meteorological Instruments, first published in 1941 with the third and final publication in 1953. This was the classic text in the field. Only recently have other texts appeared to cover this area. He also wrote three books on the history of meteorological instruments, also classics. In 1953 he wrote Vision through the Atmosphere, again, a seminal text in the field.

Middleton served on OSA's Board of Directors in the 1950s and was awarded its highest honor, the Frederic Ives Medal/Jarus Quinn Award in 1959.

He was a member of the Royal Society of Canada, of the Inter-Society Color Council, and of OSA. In addition to the Ives Medal, he was elected to Fellow of the Royal Society of Canada in 1943 and he received the Patterson Medal in 1979.

He died on 30 January 1998 in Edmonton, Alberta, Canada.