This book explains how a program works in a computer in a way that anyone can understand. The program is loaded into memory, interpreted and executed by the CPU. The structure of the program is explained in an orderly fashion using numerous diagrams. The third edition has been reviewed in its entirety, with new products and development tools, and significant additions have been made to the text and notes so that even those new to programming will not be confused. The hardware explanations and sample programs in C programming language, which were well received in the second edition, have also been updated. The supplementary chapter at the end of the book, "Let's Try C programming language! has also been revised to conform to the latest specifications. Newly written Chapter 12 covers machine learning with Python. Readers experiencing machine learning for the first time will become familiar with artificial intelligence (AI) as a way to utilize computers and programs. In addition, an explanation of Python, "Let's Try Python!" has been added to the supplementary chapter at the end of the book.