Here are some past Erik Naggum Usenet articles for your reading pleasure.
- Use SLOT-UNBOUND to lazily complete loading of objects
- Use CHANGE-CLASS to eliminate references from an instance
- An interesting memory management scheme
- Optimizing Lisp time routines; check the entire thread
- Why multiple keyword arguments are allowed, and why only the first seen are used
- Object Orientation and what it means in Common Lisp