Go language provides essential syntax and features that allows you to write your programs. These programs leverage libraries for reusable pieces of functionality and tooling for formatting code, compiling code, running tests, installing programs, and creating documentations. Libraries play a key role in the Go ecosystem because Go is designed to be a modular programming language for writing highly maintainable and composable applications. Libraries provide reusable pieces of functionality distributed as packages. You can use pac kages in Go to write software components in a modular and reusable manner to be shared across Go programs, and can easily maintain your applications. The design philosophy of a Go application is to write small pieces of software components through packages and then compose Go applications with these smaller packages. Libraries are available from the standard library and third-party libraries. When you install Go packages from the standard library, they are installed into the Go installation directory. When you install Go, the environment variable GOROOT will be automatically added to your system for specifying the Go installation directory. The standard library includes a larger set of packages that provide a wide range of functionality for writing real-world applications. For example, "net/http", a package from the standard library, can be used to write powerful web application and RESTful services.