His collection of over twenty volumes of poetry, autobiography, travel and criticism are kept at Queen's University Belfast.
His book Inglorious Soldier gives a first-hand, and one of the most detailed, accounts of the shooting of the pacifist Francis Sheehy-Skeffington.
His papers present lively and intimate accounts of the famous Irish writers whom he knew personally, such as William Butler Yeats, George Moore (novelist), Edith Anna Somerville and Katharine Tynan.
In 1963, Gibbon collaborated in the editing and publication of Michael Farrell's posthumous novel Thy Tears Might Cease.
Mrs Gibbon's father, Edward Spender, was a strong supporter of the Women's Suffrage movement in which his sister, the novelist Emily Spender played a leading role as a member of the executive committee of the Central Committee of the National Society for Women's Suffrage.
The Gibbons' home, Tara Hall, at Sandycove, County Dublin, was a literary centre and afternoon tea parties there often ran into the night.
Frequent visitors there included Irish writers such as Padraic Colum, Ulick O'Connor and Austin Clarke.