An indefatigable writer who produced over two dozen novels, as well as plays, works of philosophy, lectures and poems until she was stricken with Alzheimer’s in the late 1990s, Iris Murdoch was an equally prolific correspondent. This 600-page selection of her letters, astutely and unobtrusively edited by Avril Horner and Anne Rowe, takes the reader from her earnest teenage years in the 1930s to the final years of her life, still restlessly engaged on an aesthetic quest to define her notion of ‘the Good’, and to find in art the prime vehicle for moral enquiry. In conjunction with Peter Conradi’s 2001 biography, the letters also provide a portrait of an artist whose work closely matched the complications of her life (or vice versa), and who by her own admission found it nearly impossible to separate love, sex and friendship. "I wish I could create really different people in my novels," Iris Murdoch wrote to her oldest friend, the philosopher Philippa Foot, "but they are all me."

The trajectory of Murdoch’s career was outwardly conventional. Formidably intelligent, she progressed from public school to Oxford, taking in the membership of the Communist Party that was practically obligatory for a member of her generation and class. During the Second World War she worked at the Treasury, and then joined the UN Relief and Rehabilitation Administration to work with the vast tide of displaced persons who had been uprooted by the conflict. That early exposure to the suffering of ordinary people, as well as the death in combat of her great friend Frank Thompson, an SOE agent who was executed by the Nazis, confirmed for Murdoch the vital need for a firmly explored and defined set of ethics, in the face of a world that was capable of such evil. By the 1950s Murdoch was lecturing in philosophy and enjoying success as a novelist after the publication of her first novel, Under the Net. It was a career that saw her win the Booker Prize, secure a damehood and establish herself as one of the most significant figures in post-war English fiction (although she always stressed her Irish roots).

Devoting almost as much time to her correspondence as she did to her fiction, the letters reveal not only the tangle of her personal relationships, with major literary figures like Elias Canetti, Raymond Queneau and Brigid Brophy counted amongst her friends and lovers, but also the odd compulsiveness of her need to write. Often, barely a page will separate the completion of one novel and the beginning of another, all of them written in a mode that one editor refers to as "mystical realism", and which Murdoch herself thought of as being firmly in the "Anglo-Russian tradition", "full of heterogeneous stuff." While philosophy was the cornerstone of her professional life, from her wartime exposure to Sartre and Existentialism to her early engagement with post-structuralism (she must have been one of the very first people in Britain to read Derrida), Murdoch’s reputation rests on her 26 novels, although it’s a reputation that has in recent years seemed fairly insecure. It took her a while to find a style that she was comfortable with, and although the novels develop from the French-inflected philosophical realism of her debut to something stranger and more baroque in late works like The Green Knight, they fundamentally remain in that 19th-century tradition. Despite this, her novels’ defining characteristic is perhaps their sense of exploration or quest, rather than their more conventional narratives. Above all, they give the appearance of being laboratories for moral or metaphysical speculation, filtered through a mad harlequinade of love and sex and untainted not so much by self-reflexivity as by any kind of irony or cynicism. Falling between the philosophical stools of Anglo-American logical positivism and continental critical theory, Murdoch’s search for Platonic absolutes can now seem old-fashioned, and all the Brunos, Octavians, Montagues and Ruperts who frolic through her pages can make each book skate dangerously close to that semi-mythical beast, the Hampstead adultery novel. But she was keen to defend naturalistic character from "the consolations of form", and saw those characters’ pursuit of love as a way to dramatise the struggle to escape the bounds of egoism and find true freedom in the perception of ‘the Other’. It was a struggle she engaged with throughout her own life, and although Horner and Rowe sensitively acknowledge the hints of deception and selfishness in Murdoch’s conduct with other people, the letters are full of examples of her tolerance and her genuine interest in the inner lives of her friends. They can move engagingly from a rough, self-deprecatory account of her failures and achievements to a series of penetrating asides about human nature and the power of art to illuminate it.

With a not entirely innocent gift for friendship and love ("When I am in love I am INSANE"), some of Murdoch’s correspondents stay with her for decades, and were clearly dedicated to her. She was a major figure in what was still a mostly homogenous literary environment, and these fascinating letters go some way towards demonstrating what made her such a charismatic figure to so many people.