Coleman then travelled to the United Kingdom to study political philosophy at the London School of Economics under Michael Oakeshott, completing a thesis on the French philosopher Georges Sorel.

Together they had two daughters, Tanya, who became a lawyer and later wife of Deputy Liberal Leader Peter Costello, Ursula, a children's writer, and a son William, who is an economist.

[8] In these years he published his first books Australian Civilization, a symposium which brought together writers and critics ranging from Manning Clark and Max Harris to James McAuley and Vincent Buckley; Obscenity Blasphemy Sedition, a study of the first 100 years of censorship in Australia; the anthology The Bulletin Book; and Cartoons of Australian History, with cartoonist Les Tanner.

[12] At the 1978 election, Coleman and the Coalition campaigned on a platform based around the spectre of "Whitlamism" and attempted to undermine the strong central leadership of Wran.

Coleman himself lost his seat of Fuller to Hunter's Hill Municipal Council Alderman, Rodney Cavalier, a result that had been anticipated by some.

On leaving politics, Coleman resumed his career as a full-time writer, publishing widely both journalism and books, including a major history of the intellectuals and the Cold War, The Liberal Conspiracy.

The Congress for Cultural Freedom and the Struggle for the Mind of Postwar Europe[16] and biographical works on the Australian poet James McAuley, comic artist Barry Humphries, film director Bruce Beresford and economist Heinz Arndt.

During this period he also recorded interviews, held by the National Library of Australia as part of the oral history project, with leading Australian figures in journalism, arts, law, economics, philosophy and politics, including Hugh Atkinson, Garfield Barwick, Bruce Beresford, Jim Carlton, Madge Eddy, Charles Higham, Kenneth Jacobs, Eugene Kamenka, Michael Kirby, Kenneth Minogue, Barry Oakley, Desmond O'Grady, Clyde Packer, John Passmore, Peter Porter, Adrian Rawlins and Amy Witting.