Inklings (act. 1930–1960), was an informal literary discussion group whose membership was made up primarily of academics and other affiliates of the University of Oxford. As enthusiasts of literature—and especially of fantasy and narrative fiction—club members met regularly from the 1930s to the 1950s, principally to read and discuss their works in progress. Core members included the writer and Christian apologist C. S. Lewis, the author J. R. R. Tolkien, and Charles Williams, staff editor at Oxford University Press (1908–45).

Lewis was the driving force behind the group and appropriated the name Inklings from a literary society that had been established in 1931 by Edward Tangye Lean, an undergraduate at University College, Oxford. According to Tolkien, when Lean graduated in 1933, the name 'was then transferred … to the undetermined and unelected circle of friends who gathered about [Lewis] and met in his rooms at Magdalen' (Carpenter, Inklings, 67). Both men used the name 'informally and half jestingly' (ibid., ix) for as Tolkien observed, it was 'a pleasantly ingenious pun in its way, suggesting people with vague or half-informed intimations and ideas plus those who dabble in ink' (Letters of Tolkien, 36). These dabblers—the group's biographer Humphrey Carpenter fixes the official number at nineteen—were never members of a formal club with recognizable membership, rules, agendas, officers, or elections.

Instead they were what Lewis's biographer A. N. Wilson refers to as a 'gathering of cronies', friends and associates with similar interests (Wilson, xii). They included the author and philosopher (Arthur) Owen Barfield; Jack Bennett, Lewis's successor as professor of medieval and Renaissance English at Cambridge; the biographer and critic Lord David Gascoyne- Cecil; the scholar, author, and theatre producer Nevill Coghill; Jim Dundas-Grant (1896–1985), commander of the Oxford University naval division; H. V. D. (Hugo) Dyson (1896–1975), lecturer and tutor in English at Reading and Oxford universities; Adam Fox (1883–1977), professor of poetry at Oxford (1938–43), dean of divinity at Magdalen College, Oxford, and canon of Westminster Abbey; the classical scholar Colin Hardie [see under Hardie, William Ross]; Robert Havard (1901–1985), physician and author of the clinical appendix to C. S. Lewis's Christian apologetic text The Problem of Pain; W. H. (Warnie) Lewis (1895–1973), soldier, amateur historian, and C. S. Lewis's only sibling; Gervase Mathew (1905–1976), writer and lecturer in Byzantine studies at Oxford University; the historian and political scholar Ronald Buchanan McCallum; Courtenay Edward Stevens (1905–1976), lecturer in ancient history at Oxford, and J. R. R. Tolkien's youngest son, Christopher (b. 1924), an Oxford tutor in English language (1964–75) and editor of his father's posthumously published works. The group's final two members were the writer and poet John Wain and Charles Leslie Wrenn (1895–1969), professor of Anglo-Saxon at Oxford (1946–63).

Writers and poets such as W. H. Auden, T. S. Eliot, Dorothy L. Sayers, and Roger Lancelyn Green (a former student and biographer of Lewis) have all been described as Inklings, but they were friends of specific members rather than part of the group itself. As with many Oxford societies during this time, membership was exclusively male, and members reacted with discomfort and some resentment when Lewis later made attempts to include his American wife, the Jewish writer and former communist and atheist Joy Gresham (née Davidman).

In the early days discussions and readings generally took place on Thursday evenings in Lewis's rooms at Magdalen College, and sometimes in Tolkien's rooms at Merton. After war was declared in 1939 the London office of Oxford University Press moved to Oxford, and with it the staff editor Charles Williams. Though a Christian, Williams was interested in the occult. He was a prolific writer of what T. S. Eliot termed 'supernatural thrillers' and eagerly presented his works in progress to the group. Though manuscript readings took place only in college, later Inklings meetings were held at the Eagle and Child pub on St Giles, referred to by the group as either the Bird and Baby or the Bird. Texts that were read and discussed at Magdalen included Tolkien's fantasy works The Hobbit (published 1937) and The Lord of the Rings (published 1954–5), part one of Lewis's science fiction trilogy, Out of the Silent Planet (published 1938), and Williams's novel All Hallows' Eve (published 1945).

When they had met, Tolkien and Lewis had been at odds over the English syllabus at Oxford, with Tolkien promoting the interests of language and philology, and Lewis asserting the need for students to study post-Chaucerian works of literature such as Spenser's The Faerie Queene. The pair quickly forgot their differences when they discovered a mutual love of what Lewis termed 'Northerness', anything from Norse mythology and legend to the Scandinavian-inspired operas of Richard Wagner, like Die Walküre (The Valkyrie), Siegfried, and Götterdämmerung (The Twilight of the Gods). To his great pleasure, Lewis experienced a feeling with Tolkien that he describes both in his autobiography, Surprised by Joy (p. ix) and in his section on friendship in The Four Loves (1960):

Friendship arises out of mere Companionship when two or more of the companions discover that they have in common some insight or interest or even taste which the others do not share and which, till that moment, each believed to be his own unique treasure (or burden). The typical expression of opening Friendship would be something like, ‘What? You too? I thought I was the only one’.

p. 78

Lewis's use of the word 'burden' is significant, for Tolkien had hitherto kept his love of myth-making a secret, and in a later, memorable lecture referred to his creation of private languages as a 'secret vice' (J. R. R. Tolkien, The Monsters and the Critics and Other Essays, ed. C. Tolkien, 1986, 2006 edn, 198). He was only eighteen when he first imagined using his love of 'the nameless North' (Carpenter, Inklings, 29) to create his own cycle of mythology. This was an idea that greatly appealed to Lewis, who had once exclaimed: 'Tollers … there is too little of what we really like in stories. I am afraid we shall have to try to write some ourselves' (Wilson, 153). It was this conclusion that inspired Lewis to write the first of the Chronicles of Narnia and to work on The Lion, the Witch and the Wardrobe began as early as 1939. As far back as 1926 Tolkien had organized informal literary meetings for dons interested in reading Icelandic sagas and myths. They had called themselves the Coalbiters, from the Icelandic word kolbítar, which means 'men who lounge so close to the fire in winter that they bite the coal' (Carpenter, Inklings, 27). This club gradually metamorphosed into the Inklings, with Tolkien, Lewis, and Williams remaining at the centre of its activities.

Many of the works discussed by the Inklings also featured Christian themes, either overt or implicit. Although the group counted an atheist and anthroposophist among its number, most members were Christians. Tolkien and Hugo Dyson also played a pivotal role in Lewis's now famous conversion from theism to Christianity. On 19 September 1931 Dyson and Tolkien had gone to Magdalen to dine with Lewis and went on to enjoy an after-dinner stroll along Addison's Walk, a leafy path that runs through part of the college along the River Cherwell. The conversation turned to myth and Christianity. Returning to Lewis's rooms, they talked until 3 a.m. and, as Lewis later wrote to his lifelong friend Arthur Greeves: 'I have just passed on from believing in God to definitely believing in Christ—in Christianity … My long night talk with Dyson and Tolkien had a good deal to do with it' (Carpenter, Inklings, 45). From this point, Lewis went on to worldwide fame as a Christian apologist, producing such texts as The Screwtape Letters (1942), The Great Divorce (1945), Miracles (1947), Mere Christianity (1952), and God in the Dock (1971).

The importance of the Inklings as a literary society—albeit an informal one—in its effect on the writings of Tolkien, Lewis, and Charles Williams should not be underestimated. One of Williams's best novels, All Hallows' Eve, was improved as a result of suggestions made by the group. Encouraged by Lewis's enthusiasm and suggestions, Tolkien too pressed on with his imaginative cycle of myth and the resulting trilogy, the mammoth Lord of the Rings, went on to sell millions of copies in over forty languages. Lewis's Chronicles of Narnia have also enjoyed enduring popularity and have become classics of children's literature. In addition to producing works of fantasy Tolkien and Lewis sought to legitimize it, and through their association and friendship both produced essays and lectures that were instrumental in making the study of fantasy a credible academic pursuit. In his now famous Andrew Lang lecture, 'On faerie stories', Tolkien defended fairy tales and fantasy against charges of childishness and escapism, while Lewis went on to write Of This and Other Worlds (1982), a collection of scholarly essays on fantasy and science fiction. Outside Britain, Lewis is arguably famous more for his Christian apologetic texts than for any of his works of fantasy discussed with the Oxford group. However, if his letter to Arthur Greeves is to be believed, the catalyst for his conversion may also be attributed to a prolonged conversation with two fellow Inklings.