C# and .NET remain the backbone of modern enterprise and cross-platform development. Whether you're building high-performance websites and services on Windows or Linux or desktop apps that run on Windows and macOS, the .NET ecosystem provides a mature yet constantly evolving foundation for software development. With the release of C# 14 and .NET 10, developers now have access to a more powerful toolset. This tenth edition has been thoroughly updated to reflect the latest features. It begins with a deep grounding in object-oriented programming and then walks you through building, testing, and debugging functions, as well as managing resources with .NET libraries. You'll work with data using LINQ and serialization, handle filesystem operations, and integrate new features like numerical string comparisons and OrderedDictionary improvements. This book explains C# 14 updates, such as field modifiers, partial events, and instance constructors, in a real-world context. It also guides you in building practical projects with ASP.NET Core 10, exploring Blazor and Minimal API web services that support AOT compilation-ideal for microservices and containers. By the end of the book, you'll be ready to ship professional websites, services, and tools across platforms, confident in your ability to build software that's maintainable, efficient, and aligned with modern .NET development.