Jaqueline Tyrwhitt was a pioneer in the field of town planning. In an international career spanning sixty years, she practised as a landscape architect and town planner in addition to teaching and research, and contributed greatly to the professional associations in her field, particularly to the Congrés Internationeaux d'Architecture Moderne. In later years, she edited the international journal, 'Ekistics'.
Tyrwhitt was born in South Africa but moved to London at an early age. Initially her career was in garden design and landscape architecture, with some social and economic planning projects. Following periods of study in London and Berlin, her interest in town planning intensified. She taught courses in London during and after World War II and embarked on a lecture tour of Canada and the USA in 1945. She took up posts at the New School of Social Research in New York in 1948, Yale University and Toronto in 1951 and Harvard in 1955. She was Associate Professor of Urban Design at Harvard University from 1958-1969 and acted as a United Nations consultant on housing and education programmes. With Constantin Doxiadis she founded the journal, 'Ekistics', in 1955 and moved permanently to Greece in 1969.
Tyrwhitt stated that Sir Patrick Geddes was perhaps the most important formative influence on her career. In her teaching she emphasised the need for an interdisciplinary and holistic approach to planning, the use of the region as a planning unit and the importance of social and economic factors. Geddes' use of 'thinking machines' and other diagrams made a particular impression on her. She was instrumental in bringing Geddes' town planning theories to a wider audience after his death in 1932.