PEP 20, also known as "The Zen of Python," is a collection of guiding principles for writing computer programs in the Python programming language. It emphasizes simplicity, readability, and the importance of explicitness in code. These principles help developers create clean and maintainable software. The document consists of 19 aphorisms, such as "Beautiful is better than ugly" and "Readability counts." These statements serve as a philosophical foundation for the Python community, encouraging best practices and a shared understanding of what makes good code. Overall, PEP 20 promotes a culture of clarity and efficiency in programming.