[The Warp Speed Introduction to CLOS] is an extremely short overview of the Common Lisp Object System (CLOS). Newcomers to CLOS are often intimidated by its apparent complexity and possibly confused by its unusual approach. For a long time I considered CLOS to be “too hairy”, but after working on a large project that made heavy use of CLOS, I found that CLOS is actually one of the simplest and easiest object systems to understand and use. The more complex parts of CLOS can be safely ignored.
(via jrm)