It is 2026, and a language model can generate a lexer, a type checker, and a working compiler in seconds. So why learn to build them by hand? Because a generated artifact is an assertion - and an assertion you cannot evaluate is not knowledge, it is a hope with good syntax. The value was never in the typing. This book carries one language - Lark, the Lambda Affine Resource Kernel - from a real instruction set to a machine-checked proof that its meaning is sound, treating the hardware, the theory, and the proof as a single argument. You begin at the silicon and build upward through lexer, parser, type system, interpreter, and optimizer, to a code generator that runs Lark as native code on an affordable Raspberry Pi Pico 2/2W. Theory is earned, not assumed: Hindley-Milner inference, affine ownership, and traits, each introduced when the implementation needs it. And the book teaches the discipline that code-generating tools demand - an interpreter that defines what a program means, a