In this chapter, you will be acquainted with tools that help you to run and manage your Haskell source code. The section Glasgow Haskell Compiler presents some general guidance on setting up tools to compile and run Haskell source code. In the section Say hello to my little friend, you will be shown how to load the interactive environment for Haskell as well as how to compile a Haskell source file. Finally, the section Any comments? details how to comment your Haskell source code.