Don?t count C out. The classic programming language remains the backbone of many modern software systems including operating systems, relational databases, libraries, embedded systems, and even the core components of other programming languages. This book teaches C23 while also building a foundation that strengthens your programming skills regardless of what language you normally program in.  Starting with a tour of C, it highlights C?s core concepts using example programs to give you the flavor of C. Next, it covers the entire C23 language including topics not often covered elsewhere such as undefined behavior, assertions, atomic variables, lock-free programming, debugging, advanced use of the preprocessor using _Generic, and more. Finally, it gives extended examples of how features common in modern programming languages might be implemented?including lists, maps, dynamic dispatch, and exceptions. This book includes many in-line notes containing commentary, explanations for why something is the way it is, historical context, best practices, and details often glossed over in modern languages. Additionally, it gives examples that evolve with the introduction of new language features. What You Will Learn: Write programs in C using the new features introduced in C23. Explore advanced or obscure parts of C not explained well elsewhere, if at all. See how strings, lists, maps, dynamic dispatch, and exceptions might be implemented from scratch to understand what?s really going on in whatever language you program in. Who This Book is for: Professional programmers, computer science instructors, students or experienced hobbyists who understand programming language concepts (variables, statements, loops, functions, arrays, classes, objects, etc.) and have basic familiarity with algorithm characterization given in ?big O? notation.