- Code: The Hidden Language of Computer Hardware and Software

Clear and entertaining

An engaging and accessible exploration of how computers really work. The author breaks down complex concepts into simple, relatable explanations, making topics like binary, logic gates, and basic circuits far less intimidating. For newcomers, it’s a great way to build a foundational understanding of computer theory with just a touch of electrical engineering. As someone with a technical background, I still found it entertaining; the examples and analogies added fresh ways to frame ideas I already knew. It’s the kind of book that can bridge the gap between “I use computers” and “I understand what’s happening under the hood.” Highly recommended for anyone curious about what makes hardware and software tick, whether you’re starting from scratch or just want a new perspective.

The best book to enter the field. Grateful that Charles Petzold decided to write it, even happier this was one of the first books I picked up. Recommend to everyone wanting to become a programmer, or just interested in computers.

This is an amazing book for the right kind of reader. It's a lot like Euclid's Elements but for computers as it leads the reader through designing a computer from first principles and builds to the point of creating software and adding peripherals. It's an amazingly clear but slightly challenging read. I have given this book as a gift many many times. It's an absolute classic in my opinion.

Disclaimer: I owned the first edition for years and read it a dozen times, mainly for pleasure since it’s not only informative but also just enjoyable to read. I’m a professional software architect and have dozens of textbooks on computer science and engineering so I’ve been around the block. This is the kind of book I would buy all for all my friends (if I had more than a couple) and family members (if they were even slightly into computers, which they aren’t sadly). Petzold does an exceptional job at describing digital logic and guides you through building a conceptual CPU from very first principles. I think his bottom up approach is the way to go and has helped me understand complex topics in an extremely simple way. When I’m not reading fiction, this is my go to bedtime reading. The second edition has about 100 more pages than the first and some content has been completely reworked and it’s great. If you ever had even a passing interest in knowing how computers work at a very fundamental level, get this book!

As an ardent reader of the past 1st edition, I was fairly excited to get the latest version. That is, until I encountered the history chapter of the new edition. For one thing, what I do NOT understand in this second edition is the newly added description of August Ada Byron (countless of Lovelace). The author claims it was Babbage who was the first programmer to design the engines, not Ada. I am not trying to start a futile argument here about who has more or fewer contributions, etc. What I am trying to assert here is that it is undisputed that Ada (unless the new evidence arises) left *the very first demonstration* of what this seemingly imaginary machine, which didn't even physically exist, was capable of through her program. Because Babbage designed the engine itself, that doesn't automatically put him in the position of a programmer (despite Babbage being a brilliant engineer/scientist and may have had a simple or detailed program in his mind). However, it was Ada who gave a definite touch to programming concepts that ultimately led to modern-day programming. Ada deserves more recognition than a mere "tutorial writer," and she is certainly entitled to the title she deserves. Other than that, like the previous edition, this book is a must-read for people who are from related/unrelated fields. I always loved the 1st edition, and I would do too with the 2nd. Still, I think history should always be approached with more care, particularly if matters have potential controversies.

The second edition is well written. Charles P. is known for his excellent books on programming and architecture. If you want to know how computers work, this book is for you. Be aware there are some errors (see errata on the internet). I corrected everything in 10 mins, no big deal.

A very basic book that should be mandatory for anyone working with computers, from basic coding to electrical engineers. It’s easy to read, goes over the whole process from early communication with flash lights to switches and routers, to how code works with the computers hardware. As a data scientist without much of a computer science background, this was a delight.

Im currently building my foundations in computers on a lower level one book at a time. I came into software engineering from a sales background. Over time, I’ve realised that while practical experience teaches you a lot, it can leave gaps in the deeper why behind how computers actually work and why software behaves the way it does. So I’ve been creating my own structured learning path to fill those gaps, starting from the ground up. The first book I chose is this one right here! It’s not a typical programming book. It starts with how humans first used codes to communicate through Morse code, telegraphs, and switches and slowly builds toward how those same ideas evolved into modern computers. What surprised me most is how much of computing is built on very simple logic. At its core, everything reduces to circuits making yes/no decisions and when you chain enough of those together, you get adders, memory, and eventually an entire processor. Reading it connected a lot of dots for me like how information becomes binary, how logic gates combine to perform arithmetic. It made computing feel less like magic and more like a long, logical sequence that starts with electricity and ends with the systems we work with every day. If you’re self taught, or you feel like you’ve jumped straight into frameworks and languages without really understanding what’s underneath, I’d highly recommend this book. It helped me see computers as one continuous chain of reasoning from Morse code to microprocessors.

Interessting, great book

One of the best, if not the best, books on computing… nice touch with the colored diagrams

Good concise write up on how hardware and software interact inside an Intel 8080 cpu.

Great book for a curious child or adult who wants to know how computers work. Less hands-on than Nisan and Schocken's book. Ideally, get both!