# Code by Charles Petzold

7 Hacker News commenters recommended Code by Charles Petzold and 1 criticized it, November 2025 to November 2026. It was recommended in 5 of 13 months.

**Verdict:** Recommended for explaining how a digital computer works, from relays up to computation, in readable prose. Critics note that most images are missing from the latest printings.

## Why people recommend it

- Explains how computers work (2 comments): "He explains how a digital computer works. Not sophisticated ones, not how it works on silicon, but how you turn relays into computation." ([source](https://news.ycombinator.com/item?id=49576073)) "For those interested in learning about the inner workings of computers, I also recommend the book Code by Charles Petzold." ([source](https://news.ycombinator.com/item?id=47027613))
- Called the must-read on this topic (2 comments): "This is the book to read if you are interested in the topic" ([source](https://news.ycombinator.com/item?id=48785295)) "Mr Petzold's book, Code, is marvel and you should read it" ([source](https://news.ycombinator.com/item?id=47386206))

## Alternatives hackers recommend

- [The Garbage Collection Handbook by Jones, Hosking and Moss](https://hackerapproved.com/p/garbage-collection-handbook.md): 16 recommend
- [Beej's Guide to Learning Computer Science by Brian Hall](https://hackerapproved.com/p/beej-s-guide-to-learning-computer-science.md): 15 recommend
- [Code: The Hidden Language of Computer Hardware and Software by Charles Petzold](https://hackerapproved.com/p/code-the-hidden-language-of-computer-hardware-and-software.md): 12 recommend
- [The Unix-Haters Handbook by Garfinkel, Weise and Strassmann](https://hackerapproved.com/p/unix-haters-handbook.md): 8 recommend
- [The Annotated Turing by Charles Petzold](https://hackerapproved.com/p/annotated-turing.md): 5 recommend

## Where to get it

- [See price on Amazon](https://www.amazon.com/dp/0137909101?tag=hackerapprove-20) (affiliate link)
- [Bookshop.org](https://bookshop.org/a/130825/9780137909100) (affiliate link)

## Cite as

Hacker Approved, "Code by Charles Petzold", https://hackerapproved.com/p/code/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).