CODE: The Hidden Language of Computer Hardware and Software by Charles Petzold is a nonfiction book aimed at adult audiences interested in programming languages, software development, and machine theory. Published by Pearson Education in 2000, this textbook provides a comprehensive look at the inner workings of computer hardware and software through its 400 pages. Illustrated and presented in a trade paperback format, this book offers a detailed exploration of the hidden language behind computer technology, making it a valuable resource for those looking to deepen their understanding of the IT world.