Here's a small collection that relates to some Tolkien-related conferences (in whole or in part) which took place from 1966 to 1970:

Tolkien Papers

This is a first printing (from February 1967) of the proceedings of the Tolkien Festival which took place at Mankato State College in Minnesota in October 1966. This is generally accepted as having been the very first Tolkien conference.



Tolkien Journal no. 10

This issue came out in November 1969, and contains several papers grouped under the heading Proceedings of the First Annual Tolkien Conference, Part I - a conference which took place at Belknap College in New Hampshire in October 1968.



Tolkien Journal no. 11 / Orcrist no. 3

This issue contains a series of papers that were presented at the Secondary Universe Conference at the University of Wisconsin at Milwaukee in May 1968. That conference covered both fantasy and science fiction, though the special issue of Arts in Society which published the proceedings was forced to omit the fantasy ones due to space constraints.



Mythcon I Proceedings

This publication contains a wealth of papers from the first annual Mythopoeic Conference which took place at the Claremont Colleges in California in September 1970. The copy I have isn't an original - it's a reprint which can be ordered directly from the Mythopoeic Society.



Shadows of Imagination

This unassuming library copy is a second edition of a collection of essays edited by Mark Hillegas, which (per Hillegas in his introduction) had its origins in a conference named The Fiction of C. S. Lewis and J. R. R. Tolkien which took place at the 81st Annual Meeting of the Modern Language Association of America. That Meeting took place over 3 days in December 1966, only 2 months after the event at Mankato State College.