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Departmental homepageProfessor Johnstone entered St John's College as an undergraduate Scholar in 1966 and, except for a brief period after completing his PhD, has been a resident member of the College ever since, becoming a Research Fellow in 1975 and a College Lecturer in 1979. In the University, he became an Assistant Lecturer in 1979, a Lecturer in 1982 and a Professor in 2002.
Although he retired in 2016, Professor Johnstone still regularly teaches a lecture course on category theory for Part III of the Mathematical Tripos, and also regularly supervises undergraduates in St John's.
Professor Johnstone's research interests are in category theory, in particular topos theory. He wrote the first published book on the subject, as well as a larger two-volume account published by Oxford University Press in 2002. In addition to numerous research papers, he has also published a book on stone spaces and an undergraduate textbook on logic and set theory.
Topos Theory (Academic Press, 1979; reprinted by Dover Publications in 2013)
Stone Spaces (Cambridge University Press, 1982)
Notes on Logic and Set Theory (Cambridge University Press, 1987)
Sketches of an Elephant; a Topos Theory Compendium (Oxford University Press, two volumes published in 2002, volume 3 still in preparation)
