KeyKos and its ilk

The KeyKos Architecture” is a paper that appeared in the October 1985 Operating Systems Review. It is a high density introduction to the architecture of KeyKos.
Here is perhaps the most complete collection of papers about Keykos.
Here are yet more.
The Keykos programming manual is here. A Hydra book: William Allan Wulf, Hydra C.mmp: An Experimental Computer System, McGraw Hill,
June 1981 ISBN: 0070721203
Hydra clue.

The following book describes several capability based systems and their software.

Henry M. Levy, Capability Based Computer Systems, Digital Press, 1984.

Juicy History of Windows