I built a Lisp over a weekend some 20 years ago - 1989 I think - following the instructions and methods in Henderson's book. Google for LispKit and you'll find

I built a Lisp over a weekend some 20 years ago - 1989 I think - following the instructions and methods in Henderson's book. Google for LispKit and you'll find out probably as much as I knew back then. I read the book during the week, then implemented it all in about 24 hours over Saturday and Sunday. Run first time. Never did anything with it, though ...