List of Books about the Roundtable Groups:
Continuing the Inquiry: the Council on Foreign Relations from 1921-1996 by Peter Grose at cfr.org:
https://cdn.cfr.org/sites/default/files/book_pdf/Continuing_The_Inquiry.pdf

Post-War Worlds by P. E. Corbett:
https://archive.org/details/in.ernet.dli.2015.502434

Problems of the Pacific. Proceedings of the Second Conference of the Institute of Pacific Relations, Honolulu, Hawaii, July 15 to 29, 1927 edited by J. B. Condliffe:
https://archive.org/details/problemsofpacifi0000jbed

The Anglo-American Establishment by Carroll Quigley
http://www.carrollquigley.net/pdf/the_anglo-american_establishment.pdf

The British Commonwealth and the Future: Proceedings of the Second Unofficial Conference on British Commonwealth Relations, Sydney 3rd-17th September, 1938” edited by Henry Vincent Hodson:
https://archive.org/details/britishcommonwea00comm/page/n7/mode/2up

The Council on Foreign Relations. A Short History by George Gavrilis at cfr.org:
https://www.cfr.org/sites/default/files/pdf/centennial-book.pdf

The Milner-Fabian Conspiracy: How an international elite is taking over and destroying Europe, America and the World by Ioan Ratiu
https://archive.org/details/tmfc_20240507

The Shadows of Power: The Council on Foreign Relations and the American Decline by James Perloff:
https://archive.org/details/ShadowOfPowerTheCouncilOnForeignRelationsAndTheAmericanDecline

The Wise Men by Evan Thomas and Walter Isaacson:
Can't find a link.

Tragedy and Hope by Carroll Quigley
http://www.carrollquigley.net/pdf/Tragedy_and_Hope.pdf