Objective-C serves as the primary programming language for developing applications on both OS X and iOS platforms. As an extension of the C programming language, it offers robust object-oriented features alongside a dynamic runtime environment. The language retains the syntax, basic types, and control flow statements of C, while introducing additional syntax for class and method definitions. Furthermore, it enhances language capabilities with built-in support for managing object graphs and utilizing object literals, allowing for dynamic typing and binding that defers many tasks until runtime. While creating applications for OS X or iOS, developers predominantly engage with objects, which are instances of Objective-C classes; some are provided by frameworks like Cocoa or Cocoa Touch, while others are custom-built by the developer. Ultimately, mastering Objective-C can significantly improve your ability to create sophisticated and efficient applications for Appleās platforms.