Lewis and Tolkien met in 1926. They formed the nucleus of a group of friends who were joined in 1939 by Charles Williams who had moved from London to Oxford. The Inklings was never an official society. It had no rules, nor were there official members, but their influence upon English Literature was quite remarkable. In addition to a love of literature the members shared the same values, and their writings developed the same themes. They were, in the main, deeply religious and favoured tradition over modernity. Their ideas contrasted sharply with the general intellectual and literary spirit of their times, and although they had a certain fame, they also had their detractors.
Barfield described the thing that united the Inklings as "the yearning for infinite and unattainable, the conviction of the dignity of man and his part in the future history of the world conceived as a kind of progress towards increasing immanence of the divine in the human, the idealisation of love between sexes, the opposite of tragedy, the happy ending". In some respect this group could be characterised as the Oxford Romantics.
An excellent study of the Inklings has been written by Humphrey Carpenter and is entitled "The Inklings: C.S. Lewis, J.R.R. Tolkien, Charles Williams, and their frieds" (1981, New York, Ballantine Books) Two worthwhile books about C.S. Lewis are "C.S. Lewis - A Biography" by A.N. Wilson (1991, London, HarperCollins) and "Jack - C.S. Lewis and His Times" by George Sayer (1988, London, Macmillan). An interesting examination of Charles Williams is contained in "Charles Williams - An Exploration of His Life and Work" by Alice Mary Hadfield (1983, New York, Oxford University Press) There are assuredly many more books that have been written and published about this extraordinary group. The selection that I have noted is from my own library.
The following Web Sites may be of interest for those who wish to follow
the road that the Inklings trod
Into the Wardrobe - The C.S.Lewis Page
C.S.Lewis and the Inklings Home Page
The Charles Williams World Wide Web Page
All Hallows Eve: A Reading Guide - A Guide to All Hallows Eve and the Life and Work of Charles Williams
The Owen Barfield World Wide Web Site
The Inklings Webring
The Golden Key:The George McDonald WWW Page
The Inklings Site List