David Armstrong was born in Whitley Bay on 9th July 1926 and died suddenly at his home in Ponteland, near Newcastle-upon-Tyne on 8th February 2000. The son of a bank clerk, David attended Whitley Bay Grammar School, before proceeding to study agricultural chemistry at Kings College, Durham University (later renamed Newcastle University). On graduating with an Honours Degree in 1946, followed by an MSc and a PhD in 1951, he stayed in Newcastle as a lecturer in agricultural chemistry before spending a year at the University of Illinois, USA, working with H H Mitchell. He then joined the staff of the Nutrition Department at the Hannah Research Institute in 1954 and over the following nine years, working with K L Blaxter (later Professor Sir Kenneth Blaxter FRS) and N Graham, he contributed substantially to present day understanding of the energy metabolism of farm animals. Indeed, their studies set many of the foundations for modern ruminant nutrition research.