David Both 
Image by: opensource.com CC-by-SA 4.0
Last Updated on February 3, 2026 by David Both
Image by: opensource.com CC-by-SA 4.0
Brian W. Kernighan’s second edition of Understanding the Digital World is worth a read for computer enthusiasts of any skill level.
I read a lot of books. I especially like to read books about computers, Linux, and the digital world we live in. I also enjoy reading books on the history of computing about and by the people who helped make this digital world what it is today.
Imagine my excitement when I discovered the new second edition of an important book by Brian W. Kernighan, one of the leading figures in the creation of Unix, author or co-author of many influential books, and a professor of Computer Science at Princeton University. Understanding the Digital World combines computer history, technology, and personal story, along with discussions about how today’s technology impacts our privacy.
Kernighan teaches a course at Princeton each year, “Computers in Our World,” intended for computer users who are not Computer Science majors. He wrote this book to bring much of the information contained in that course to the world at large.
Kernighan starts with an exploration of the technology itself. The title of Chapter 1 is, “What is a Computer?” Covering the CPU and how it works, he describes various forms of storage, including RAM, cache, disk, and other types of secondary storage, and how they all work together. After this overview of the hardware, he describes algorithms, how they are used to solve problems, and how they get incorporated into computer programs. In later chapters, Kernighan discusses the internet, the TCP/IP protocols that drive it, and some of the tools used to communicate using the internet.
He looks at the data about ourselves (stored on our computers) that gets transmitted across the internet—with or without our permission. Although there are references to security throughout the book, Kernighan spends a great deal of these latter chapters discussing the many ways in which our data is vulnerable and ways to implement at least some level of protection.
The parts that scared me most were the discussions about how organizations can track our movements on the internet—the effects of this (and tools such as data mining) on our online experiences. I am familiar with using tools like firewalls and strategies such as using good passwords and deleting or deactivating programs and daemons that I am not using. But the ease with which we can get spied upon (there is no more accurate word for it) is appalling no matter what actions we may take.
My first inclination after reading this book was to send it to the two of my grandkids that I am helping to build gaming computers. This book is a good way for them to learn how computers work at a level they can understand. They can also learn about the pitfalls (beyond those their parents have discussed with them) about how to be safe on the internet. I also suggested to their parents that they read it, too.
It is not all gloom and doom. Far from it. Kernighan manages to scare me while simultaneously ensuring that readers understand how to mitigate the threats he discusses. In the vast majority of his scenarios, I had already implemented many of the protections he covers.
This book has made me think more closely about how I work and play on the internet, the methods I use to protect my home network, and how I use my portable devices. Kernighan’s level of paranoia is sufficient to ensure that readers pay attention while reassuring us that we can still use the internet, our computers, and other devices with a reasonable amount of safety so long as we take the appropriate precautions.
No! I am not going to tell you all of that. You’ll get no spoilers from me.
Kernighan indicates to readers the sections that may get too technical, and you can skip over them. Still, overall this is a pretty easy read and accessible even for many non-technical readers. This was intentional on the author’s part. So even if your technology quotient is fairly low, this book is still understandable. Despite the fact that he wrote the first edition of this book only five years ago, this second edition includes important new material that makes it even more applicable to today’s technology and the lightning-fast dissemination of data. I found the new section on artificial intelligence quite enlightening.
I highly recommend this book to anyone who wants to learn more about how computers work and impact privacy and security in the modern world.
