AMOP
AMOP is an acronym used in reference to the lisp book, The Art of the Metaobject Protocol, by Gregor Kiczales, and which was published by MIT Press, 1991.

AMOP chapters 5 and 6 (basically, "the MOP specification") have been kindly released into the public domain by the original authors.

As of 15 october 2017, a modern public domain online version of AMOP chapters 5 and 6 (MOP specification) is available. Full faithfulness to the contents of the book has been a top priority, which was ensured by carefully auditing the new version against the actual book, so this should be very complete and safe to use. This version was initially derived from Robert Strandh's public domain conversion to HTML.

Scanned version on Google books.

Also see: MOP, CLOS