Object-oriented programming is not a single thing. It is a family of ideas that C#, Java, and Python realize in strikingly different ways. This book teaches the paradigm by showing every concept three times — once in each language — so you can move between them without losing your footing.
It begins with encapsulation, inheritance, and polymorphism, then moves into abstract classes, interfaces, and the case for composition over inheritance. It covers design patterns, generics, exception hierarchies, object lifecycles, memory management, testing, and the anti-patterns that make OO code hard to maintain.
Every concept is presented with side-by-side code samples and a discussion of when the differences between languages actually matter. The final chapter is a complete syntax reference for classes, inheritance, interfaces, generics, exceptions, and collections across all three languages. For developers who know one language and want to master the paradigm across all three.
