My new article on the design & implementation of the CPython VM is out. It is my most comprehensive article yet, at 5500 words and 17 code listings, such as this: The VM is the most central piece of any interpreted language because this is how your code eventually executes. As a developer, learning about it can help you write more efficient code and debug complex problems. As a student or a compiler enthusiast, you can learn how a real-world language is implemented. The article covers a ton of details, such as bycode packing format, stack frames, bytecode evaluation loop implementation using switch case vs computed goto and a walk through of a toy Python program on the VM to illustrate how code executes.