Question: Was Tolkien friends with C. S. Lewis?

Inklings




The Inklings were an informal literary discussion group associated with the University of Oxford, England, for nearly two decades between the early 1930s and late 1949.[1]  The Inklings were literary enthusiasts who praised the value of narrative in fiction and encouraged the writing of fantasy.
Members

The more regular members of the Inklings, many of them academics at the University, included:[2]

Owen Barfield
J. A. W. Bennett
Lord David Cecil
Nevill Coghill
Hugo Dyson
Adam Fox
Roger Lancelyn Green
Robert Havard
C. S. Lewis
Warren Lewis (C. S. Lewis's elder brother)
J. R. R. Tolkien
Christopher Tolkien (J. R. R. Tolkien's son)
Charles Williams

William D. Marsh
Philip J. Vickery
Samuel J. Besh
Spencer H. Hayes
More infrequent visitors included:

Percy Bates
James Dundas-Grant
Colin Hardie
Gervase Mathew
R. B. McCallum
C. E. Stevens
John Wain
Charles Leslie Wrenn

Guests included: 
Roy Campbell
Eric Rücker Eddison
Meetings
"Properly speaking," wrote Warren Lewis, "the Inklings was neither a club nor a literary society, though it partook of the nature of both. There were no rules, officers, agendas, or formal elections."[3] As was typical for university literary groups in their time and place, the Inklings were all male. 
Readings and discussions of the members' unfinished works were the principal purposes of meetings.  Tolkien's The Lord of the Rings,[4] Lewis's Out of the Silent Planet, and Williams's All Hallows' Eve were among the novels first read to the Inklings. Tolkien's fictional Notion Club (see "Sauron Defeated") was based on the Inklings.  Meetings were not all serious; the Inklings amused themselves by having competitions to see who could read the notoriously bad prose of Amanda McKittrick Ros for the longest without laughing.[5]
The name was associated originally with a society of Oxford University's University College, initiated by the then undergraduate Edward Tangye Lean circa 1931, for the purpose of reading aloud unfinished compositions.  The society consisted of students and dons, among them Tolkien and Lewis. When Lean left Oxford during 1933, the society ended, and Tolkien and Lewis transferred its name to their group at Magdalen College. On the association between the two 'Inklings' societies, Tolkien later said "although our habit was to read aloud compositions of various kinds (and lengths!), this association and its habit would in fact have come into being at that time, whether the original short-lived club had ever existed or not."[6]
Until late 1949, Inklings readings and discussions usually occurred during Thursday evenings in C. S. Lewis's college rooms at Magdalen College. The Inklings and friends were also known to informally gather on Tuesdays at midday at a local public house, The Eagle and Child, familiarly and alliteratively known in the Oxford community as The Bird and Baby, or simply The Bird.[7] Later pub meetings were at The Lamb and Flag across the street, and in earlier years the Inklings also met irregularly in yet other pubs, but The Eagle and Child is the best known.[8]
Legacy
The Marion E. Wade Center, located at Wheaton College, Illinois is devoted to the work of seven British authors including four Inklings and Dorothy L. Sayers.  Overall, the Wade Center has more than 11,000 volumes including first editions and critical works. Other holdings on the seven foremost authors (G. K. Chesterton, George MacDonald, and Inklings Owen Barfield, C. S. Lewis, J. R. R. Tolkien, and Charles Williams) include letters, manuscripts, audio and video tapes, artwork, dissertations, periodicals, photographs, and related materials. Wheaton also has a creative writing critique group inspired by the Inklings called "WhInklings".
The Mythopoeic Society is a literary organization devoted to the study of mythopoeic literature, particularly the works of J. R. R. Tolkien, C. S. Lewis, and Charles Williams, founded in 1967 and incorporated as a non-profit organization in 1971.
A resurrection of the Inklings in Oxford was made in 2006; the group still meets every Sunday evening, currently at St Cross College nearby the Eagle and Child. It has similar aims and methods to the original group, albeit with somewhat gentler criticism.
Named after the Inklings is The Inklings Society based in Aachen, and their yearbook, Inklings Jahrbuch für Literatur und Ästhetik, published from 1983 by Brendow, Moers. The yearbook contains scholarly articles and reviews, dealing with Inklings members in particular, but also with fantasy literature and mythopoeia in general.
The undergraduate literary and art magazine at Miami University in Oxford, OH, is named Inklings. They also meet on Thursday nights.[9]
The Inklings in fiction
In Swan Song (1947) by Edmund Crispin a discussion takes place between Professor Gervase Fen and others in the front parlour of the Eagle and Child.
There goes C. S. Lewis", said Fen suddenly. "It must be Tuesday.

In the TV programme "Lewis", there is an episode called "Allegory of Love" in which a reborn version of the Inklings features.[10]
The Inklings also reappear in Lewis "Magnus Opus" in 2016.
The Late Scholar (2013) by Jill Paton Walsh is a sequel, set in 1951, to the Lord Peter Wimsey novels of Dorothy L. Sayers.  Peter Wimsey, now 17th Duke of Denver, is investigating a mystery in the fictional St Severin's College, Oxford with his friend Charles Parker, now an assistant chief constable.
Right," said Peter. "How about lunch, Charles? We could spin out to the Rose Revived." [on the Thames about 7 miles from Oxford]
Charles looked bashful. "I have heard," he said carefully, "that there is a pub in Oxford at which C. S Lewis often takes lunch."
"There is indeed,", said Peter. "But he lunches with a group of cronies … Right, on with our overcoats and it's off to the Bird and Babe.

Three of the founding members of the Inklings - Tolkien, Lewis, and Williams - are the main characters of James A. Owen's fantasy series, The Chronicles of the Imaginarium Geographica. (Warren Lewis and Hugo Dyson are recurring minor characters throughout the series.) The existence and founding of the organization is also alluded to, in the third novel, The Indigo King. (The timeline of the books is different from the historical timeline at points, but these are dealt with partway through the series by the explanation that the books take place in an alternate history to our own.)


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, a CS Lewis and Inklings resource blog.
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