Working at a publishing firm before the Second World War, Hart-Davis began to forge literary relationships that would be important later in his career.

After relinquishing control of the firm, Hart-Davis concentrated on writing and editing, producing collections of letters and other works which brought him the sobriquet "the king of editors".

[2] Hart-Davis was educated at Eton and Balliol College, Oxford, though he found university life not to his taste and left after less than a year.

In World War II Hart-Davis volunteered for military service as a private soldier, but was soon commissioned into the Coldstream Guards.

[5] After the war, Hart-Davis was unable to obtain satisfactory terms from Jonathan Cape to return to the company, and in 1946 he struck out on his own, founding Rupert Hart-Davis Ltd, in partnership with David Garnett and Teddy Young and with financial backing from Eric Linklater, Arthur Ransome, H. E. Bates, Geoffrey Keynes, and Celia and Peter Fleming.

They made an exception for Stephen Potter's Gamesmanship which was a short book, collected every ream of paper they could buy and printed 25,000 copies.

[8] Also in the early years Hart-Davis secured Ray Bradbury for his firm, recognising the quality of a science fiction author who also wrote poetry.

[9] Other good sellers were Peter Fleming, Eric Linklater and Gerald Durrell; but best-sellers were too few, and though the output of Rupert-Hart-Davis Ltd was regularly praised for the high quality of its printing and binding, that too was an expense that weighed the company down.

[10] A further expense was added when G. M. Young's biography of Stanley Baldwin was published in 1952; both Winston Churchill and Lord Beaverbrook threatened to sue if certain passages were not removed or amended.

[16] In retirement, Hart-Davis wrote three volumes of autobiography entitled The Arms of Time (1979), The Power of Chance (1991) and Halfway to Heaven (1998).

[21][22] They had a daughter in 1935, Bridget, who went on to marry David Trustram Eve, 2nd Baron Silsoe, in 1963, and two sons, Duff in 1936, and the TV presenter Adam in 1943.

The second marriage became dysfunctional, although husband and wife remained on good terms and stayed together until their children were grown up, when Hart-Davis and Comfort divorced.

[23] After the war, until his retirement, Hart-Davis lived during the week in a flat above his publishing business in Soho Square, returning to his main home at Bromsden Farm, Oxfordshire, at weekends.

During this period, a financial crisis arose when Westminster City Council decided that the library should no longer qualify for charitable exemption from local property tax.

[24] Public honours included honorary doctorates from the universities of Durham and Reading and a knighthood in 1967 for services to literature.

[25] Merlin Holland's Oscar Wilde: A Life in Letters (2003) was dedicated "To the memory of Rupert Hart-Davis, with love and gratitude."