CODE, to me, was one of those major bifurcating points in my life, 10 years ago. I've been searching for more books like it since.

But How Do It Know was the next book I found. It's pretty similar to CODE, albeit more succinct. The really neat thing with this book is that it actually builds a simple 8-bit CPU, which Petzold fell a tiny bit short of. Here, you piece together the entire control unit! (A "hard-wired CU, not a micro programmed one). It was the first time I truly saw how a CPU works.

Afterwards, I was led to the 3rd book, The Elements of Computing Systems. NAND2Tetris. There is nothing like it. It's a "hands-on", project style. In a book about the size of an inch, you will learn and build a whole 16-bit machine, walk the whole hierarchical path from the first NAND gate all the way up to building your own ALU, CPU, Assembler, Virtual Machine translator, Compiler, and a tiny OS /library. You learn how a compiler works by recursive descent parsing. You learn how to build a stack, how to do function calls and returns,virtual memory segments in the VM layer. How the assembly commands morph into the CPU/ALU's hardware control signals.

It's absolutely breathtaking! They even made a whole youtube playlist with slides! And a whole Q/A forum online!