Stewart was born in Edinburgh and educated at Oriel College, Oxford, where he studied English literature. He went on to study psychoanalysis in Vienna, before taking up an academic post in Australia. He had already begun writing mystery novels with a literary slant when he returned to the UK at the end of World War II. In 1949 he became a Fellow of Christ Church, Oxford. By the time of his retirement in 1973, he held a professorship within the university. His quintet of novels collectively titled A Staircase in Surrey was published between 1974 and 1978, the individual titles being: