The Task Parallel Library (TPL) is a set of public types and APIs in the .NET Framework that simplifies the process of writing multi-threaded and parallel code. It allows developers to create and manage tasks, which are units of work that can run concurrently, improving the performance of applications by utilizing multiple processor cores. TPL provides features like task scheduling, cancellation, and exception handling, making it easier to write efficient and responsive applications. By using TPL, developers can focus on the logic of their applications rather than the complexities of thread management, leading to cleaner and more maintainable code.