If you feel like you’re going to drown, please come up for air. Whether this will be a more pleasurable experience for you or not, I do not know. Yes, it’s a longer journey, but if you come along with me through the pages of this second edition, we shall dive much deeper into the internals of the CPU. That deficiency has been corrected in this second edition. Readers didn’t seem to complain, but to me it was a glaring flaw. I felt that I had gotten close to this crucial breakthrough but then I had given up. I wanted to show the workings of an actual CPU-the central processing unit that forms the brain, heart, and soul of a computer-but the first edition didn’t quite make it. Those problems would probably have been easy to fix, but there existed another aspect of the first edition that continued to bother me. And JavaScript, the programming language that has become pervasive on the web, wasn’t mentioned at all. Unicode-the text encoding that allows a uniform representation of all the world’s languages as well as emojis-got less than a page in the first edition.

The internet certainly existed in 1999, but it was nothing like what it eventually became. Phones and fingers supplemented keyboards and mice. Some of the cultural references became stale. As the years went by, the book started to show its age. I still think that my approach was sound, but I was wrong in some of the details. It was as if I were writing a book about the internal combustion engine but based on the Ford Model T. I also had a very clever trick up my sleeve: I would use ancient technologies to demonstrate universal principles under the assumption that these ancient technologies were already quite old and would never get older. Through this steady progression up the hill of knowledge, I would employ a minimum of metaphors, analogies, and silly illustrations, and instead use the language and symbols of the actual engineers who design and build computers. My original idea with Code was to start with very simple concepts but slowly build to a very deep understanding of the workings of digital computers. But Code, I was certain, would last forever.

My second book on the OS/2 Presentation Manager (the what?) became obsolete much more quickly. That one had already gone through five editions in just ten years. With much delight I realized that I had finally written a book that would never need revising! This was in stark contrast to my first book, which was about programming applications for Microsoft Windows. The first edition of this book was published in September 1999.

Code new edition charles petzold