As a student at Prince Alfred College Noel Baker was encouraged in his interest in mathematics by Form VI master Mr ‘Spenny’ Williams. He won the top Leaving Honours award, the Archibald Peake Bursary, and began mathematical studies at the University of Adelaide at the age of 16. Here he became a student and lifetime friend of George Szekeres, an early specialist in ‘functional iteration’, and wrote the first of seventy published papers.
Baker’s interests in music and language led to his study of the German language and in 1955 he was awarded a German Government scholarship to study at the University of Tübingen. During his time at Tübingen Baker obtained his doctorate and met a fellow-student from London who would later become his wife. The Bakers settled in London following his appointment in 1959 as a lecturer at Imperial College, where he remained until his retirement as Professor of Pure Mathematics in 1997.
Baker devoted the bulk of his long career in mathematics to the field of complex dynamics, that is the study of iterations of a given complex analytic function and the effect of repeated application of the function upon points of its domain. The bewildering behaviour of the wanderings of such a point was first studied in the 1920s by the French analysts Julia and Fatou, who established the fundamental properties of the fixed points of these orbits. Though the theory was largely ignored for many years it was pursued by Baker long before its revival through its links with chaos, fractals, and its popularisation through computer graphics.
Baker explored numerous aspects of the behaviour of Fatou and Julia sets and his pioneering work contributed enormously to the clarification of the subject. ‘Baker domains’ perpetuate his name as a reminder of his contribution to a subject that is a vital part of present-day mathematics.