Dr Jack Howlett, who died on 5 May 1999 at the age of 86, a Founder Fellow of the Institute of Mathematics and its Applications, was a mathematician with a special interest in numerical analysis who early recognised the power of computing methods and who strongly influenced the development of some mechanical computing machines and electronic computers as we know them today. The widespread advance of the use of computer models in all scientific disciplines was made possible thanks to the efforts of a small number of mathematicians who laid the foundations of modern numerical analysis during the late 1930s to early 1960s, a period which covered the greater part of Jack's working life and in which he was a star player.