In 1986 an American programmer published the first article ever written about Windows programming. Two years later he published the book that taught the world how to write software for the operating s

In 1986 an American programmer published the first article ever written about Windows programming. Two years later he published the book that taught the world how to write software for the operating system that would go on to run 90 percent of the computers on Earth. The phrase "look it up in Petzold" became shorthand among developers for three decades. He is 73 years old, lives in a small town in upstate New York, and published a second edition of his most famous work two years ago. His name is Charles Petzold. Here is the story, because the person who taught two generations how to build software for the most widely used operating system in history has almost no public profile in the modern tech world. Charles was born in 1953 in New Brunswick, New Jersey. He earned a Master of Science in Mathematics from Stevens Institute of Technology in 1975. In the early 1970s, before personal computers existed as a consumer product, he built a computer from scratch using a Z-80 processor and wired it to control a music synthesizer. He was programming machines before most people had ever seen one. In the mid-1980s he began writing programs and technical articles for Microsoft Systems Journal. In 1986 he published what is recognized as the first article on Windows programming ever written. He served as a contributing editor at the journal from 1985 to 2000. In 1988 Microsoft Press published Programming Windows. The book did something nobody else had done. It took the Windows API, a sprawling, undocumented, and deeply intimidating interface for building graphical software, and explained it from first principles with working C code. Every example compiled. Every explanation built on the last. The book assumed you knew C and nothing else. It became the bible for Windows development. Six editions followed, tracking the evolution of Windows from 3.0 to 3.1 to 95 to 98 to XP to 8. The fifth edition alone ran to 1,479 pages. Generations of professional programmers learned their craft from this single book. "Look it up in Petzold" became the standard response in developer forums, in offices, and in computer science departments when anyone asked how to do something in Windows. Microsoft named him a Windows Pioneer, one of only seven people to ever receive the award. He won the Microsoft Most Valuable Professional designation. He became the reference that the reference books referenced. Then in 1999 he published Code: The Hidden Language of Computer Hardware and Software. Code is a different kind of book. It starts with flashlights and Morse code and Braille. It builds, layer by layer, from relay switches to logic gates to flip-flops to registers to a working CPU. By the end of the book you understand how a computer works at the hardware level without needing an engineering degree. The writing is patient, clear, and free of jargon. The idea for Code came to him in 1987 while writing a column called "PC Tutor." It took him twelve years to write. It became one of the most beloved technical books ever published. Scott Hanselman, a Partner Program Director at Microsoft, called it "the first book about programming that spoke to me" and said it taught him "how many unseen layers there are between the computer systems that we as users look at every day and the magical silicon rocks that we infused with lightning and taught to think." In August 2022 Charles published the second edition of Code from his home in Roscoe, New York. He expanded the book, added new chapters, and built an interactive companion website at with animated circuit diagrams he made himself. He was 69 years old. Between Programming Windows and Code he published over a dozen other books. Programming Windows Phone 7. The Annotated Turing, a guided tour through Alan Turing's 1936 paper on computability. Creating Mobile Apps with Xamarin.Forms. 3D Programming for Windows. Programming in the Key of C#. He worked at Xamarin from 2014 to 2018. His personal website at charlespetzold .com is a flat page. His blog posts are written in plain HTML. There is no marketing copy. There is no newsletter. There is no podcast. A mathematician from New Jersey taught the world how to program the most important operating system in history, then wrote the book that explained how computers actually work. He is still writing from a small town in upstate New York.