He was one of the generation of students at LSE in the late 1940s and early 1950s who were to go on to have such an impact on the later development of sociology in the United Kingdom during the 1960s and thereafter, as it became established as a subject for independent study throughout British universities. However, whereas most of these luminaries were British in origin, Cohen came from South Africa and became one of several sociologists of that period from overseas who were to influence the post-war discipline.
He had left South Africa in 1948, largely out of strong distaste for the political developments there but also motivated by the belief that he would be more intellectually challenged away from the provincialism of his own country. He was thus one of that sizeable cohort of young intellectuals who formed a quiet diaspora from South Africa as it went into the long bleak apartheid years.
Cohen was intermittently involved with LSE over a period of more than 40 years. When he arrived there in 1948 to begin a BSc (Econ) degree in Social Anthropology, he had already had a distinguished previous undergraduate career at the University of Witwatersrand in Johannesburg. He graduated with his BSc (Econ) in 1951, and variously from 1952 till 1960 was a graduate student in social anthropology at LSE, pursuing several fieldwork studies in Israel between 1953 and 1958 for his doctoral research whilst also attached to the Hebrew University, Jerusalem. His focus was upon the absorption of immigrants into developing Israeli society, a subject of considerable political and practical concern to Israel in the early years after the state's foundation.
His first full-time permanent position was at the then highly influential Leicester Department of Sociology, where he was one of the contributors to its special reputation within the discipline in the 1960s. Cohen was an early member of that generation of trained social anthropologists who were able to repackage themselves into sociologists, strongly influencing how sociology developed during the 1960s, the research techniques that it used and its theoretical focuses. He was a Lecturer in Sociology at Leicester from 1960 till 1965. He returned to LSE in 1965 as a Lecturer in Sociology, became a Reader in 1967 and a Professor in 1971.
Cohen had the considerable distinction of being LSE's first Dean of Undergraduate Studies, from 1967 to 1971. He little realised at the outset the turmoils into which such a post would pitch him, but he was widely admired for negotiating the many Scyllas and Charybdises that could have ensnared a less diplomatically skilled holder of a post such as this in LSE in the late 1960s.
This was an important period to him also because it produced what will undoubtedly be his most enduring work, Modern Social Theory, published in 1968. The book had a significant impact upon the way that sociological theory came to be taught. Written with a stimulating freshness and clarity, it has the distinction, among British publications on the subject, of being among the first accessible yet scholarly books that replaced the turgid exegeses in theory that an earlier generation of sociology students had had to endure in the early and mid-1960s.
However, it would be wrong to create the impression that Cohen's only contributions to sociology concerned theory. He was genuinely diverse in his interests and published extensively in what is now usually termed ethnic studies, especially but not exclusively on Israel and on Jewish issues. Indeed, his final completed book was the partly historical Jewish Radicals and Radical Jews (1980).
He was also somewhat unusual in being especially at home in that subset of the discipline that elides into philosophy and he had many intellectual and personal contacts with philosophers at LSE. Further, he developed a strong interest and competence in psychoanalytic theory and published on the subject. At his retirement he was working on a book-length study in this area, which sadly he became too ill to complete as progressive Alzheimer's disease removed his capacity to write.
Shortly after becoming Professor, he had a term as head of the LSE Department of Sociology, an office that he held again in the mid-1980s. Properly heading a university academic department requires good management skills, tact, sensitivity and integrity. Not every academic meets all these requirements, and some meet none at all, but Cohen's terms of office as departmental head were models of competence and good sense. This is a particular achievement, given that in both periods the discipline of sociology, nationally but also within LSE, was in retrenchment and the departmental head was thus obliged to tackle the various tensions associated with consequent pressures on resources and staff.
In his professional life Cohen conducted himself with decorum and a restrained sense of humour. In private, he could be more relaxed. Widely regarded for his wit and abilities as a raconteur, he had musical skills as well as an extensive knowledge about wines. He never lost touch with events in his country of origin; during the apartheid years he had links with the ANC and with South Africa's Asian community. He was instrumental in the establishment of a fund for the education of black township children.
In assessing all the various contributions that his life made, it is hard to decide the most important. However, it cannot be denied that his sociological writings - in theory, the philosophy of science and ethnic studies - place him firmly in the traditions and history of sociology, both at LSE and in the post-war development of the discipline in the UK.
Percy Saul Cohen, sociologist: born Durban, South Africa 6 August 1928; Tutor in Social Anthropology, Birkbeck College, London 1959-60; Lecturer in Sociology, Leicester University 1960-65; Lecturer in Sociology, London School of Economics and Political Science 1965-67, Reader in Sociology 1967-71, Dean of Undergraduate Studies 1967-71, Professor of Sociology 1971-91 (Emeritus); married 1956 Ruti Moyal Nachmani (three daughters); died London 15 September 1999.