"Metaobject Protocol" でググると3番目に↓が見つかって，
ttp://www.lisp.org/mop/
んでここには
> The book The Art of the Metaobject Protocol, sometimes called the AMOP,
> includes the CLOS Metaobject Protocol specification as chapters 5 and 6.
> These chapters are reproduced here in hypertext.
とあるんだけど， >>167 はここをもう見た上で「第1-4章がないのか？」と質問してるのかな？