It starts you from scratch and I'd say it's well done, maybe even be overdone for Lisp. But you get a good introduction to the essentials of language implementation for more complicated languages.

Shameless self-promotion: I wrote a Lisp interpreter in a single assembly file for Raspberry Pi. It also starts from scratch at an even lower level, to the point of ignoring standard libraries.

https://github.com/marcpaq/arpilisp

I was inspired by jonesforth, which, if you haven't read it, is a beautiful piece of work.