Code: The Hidden Language of Computer Hardware and Software (1999) is a book by Charles Petzold that seeks to teach how personal computers work at a hardware and software level. In the preface to the 2000 softcover edition, Petzold wrote that his goal was for readers to understand how computers work at a concrete level that "just might even rival that of electrical engineers and programmers" and that he "went as far back" as he could go in regard to the history of technological development. Petzold describes Code as being structured as moving "up each level in the hierarchy" in which computers are constructed. On June 10, 2022, Petzold announced that an expanded second edition would be published on August 19, 2022 and he is building a companion interactive website.The idea of writing the book came to him in 1987 while writing a column called "PC Tutor" for PC Magazine. Source: Wikipedia (en)