This looks like an excellent way of doing a deep dive that I'm tempted to do myself, now. It looks like a fascinating historical exposition of what is indeed on

This looks like an excellent way of doing a deep dive that I'm tempted to do myself, now. It looks like a fascinating historical exposition of what is indeed one of the oldest languages in our field. But for someone who just wants the most dead simple Lisp implementation possible, there's always SICP, which ends in them writing out a basic metacircular lisp intepreter on just a few blackboards, in Scheme. Of course they skip parsing and boring details, as well as macros. But it's a good place to start.