In 1965 he returned to Cambridge University where he earned his PhD in 1968 about the French administration in Morocco. Between 1968 and 1990 he had been Secretary and Librarian of the Middle East Centre in the Faculty of Oriental Studies in the University of Cambridge. From 1980 on he dedicated the rest of his life to his master-piece Dictionary of Modern Arab History – An A to Z of over 2,000 entries from 1798 to the present day.