The Inklings were an association of writers at Oxford, some very close friends, whose activities included sharing readings from their works in progress.
In addition to C.S. Lewis, J.R.R. Tolkien, and Charles Williams, at various times they seem to have included Lewis brother W.H. Lewis, R.E. Havard, Hugo Dyson, Nevill Coghill, Adam Fox, Owen Barfield, Charles Wrenn, R.B. McCallum, Gervase Mathew, and Lord David Cecil (setting aside any quibbles about membership as inherently unresolvable).
Source: The Inklings, by Humphrey Carpenter
Background graphic copyright © 2003 by Hal Keen