CMSC 430: Design and implementation of programming languages (notes)
lively and easy-to-follow notes, even though I don't know Racket or x86 assembly
Threaded code – muforth
"Threaded code is an extraordinarily simple and elegant way to implement language interpreters. Compared to bytecoded interpreters it is quite fast, and compilers for it are essentially trivial... Because it creates a system entirely composed of uniform pieces, extensibility of the system by users is almost unlimited, and building generic tools is dramatically simplified!"