Asembly and Hardware

Easy 6502 (opcodes)
Learning 6502 Assembly
Famicom Party
GB ASM Tutorial (opcodes)
TONC
RP2040 Datasheet
RP2040 Assembly Language Programming
Apple Silicon Assembly by Examples
The Elements of Computing Systems
Reverse Engineering for Beginners
ChibiAkumas

Forth

Starting Forth
Thinking Forth

Lisp

Structure and Interpretation of Computer Programs
SICP Lectures
The Scheme Programming Language
The Little Schemer

C

The C programming Language (2nd edition)
C Programming - A Modern Approach
C Language Reference


Other High-Level Languages

HTML Beginner Tutorial
Eloquent Javascript
Javascript Tutorial
Learn Python 3 the Hard Way
Eloquent Ruby
The Well Grounded Rubyist



Math & Physics

Calculus
Linear Algebra
A First Course in General Relativity
Quantum Mechanics: the Theoretical Minimum
Quantum Field Theory in a Nutshell



Simulation

The Nature of Code
Rigid Body Dynamics
CFD Python
An Introduction to Computer Simulation Methods



Electronics

Foundations of Analog and Digital Electronics
Practical Electronics for Inventors
Making Embedded Systems



Misc. Programming

Introduction to Algorithms
Frisby's Guide to Functional Programming
Game Programming Patterns
The Little Book about OS Development
OSDev Main Page