The OpenGL Shading Language (GLSL) Version 4 brings unprecedented power and flexibility to programmers interested in creating modern, interactive, and graphical programs. It allows us to harness the power of modern Graphics Processing Units (GPUs) in a straightforward way by providing a simple yet powerful language and API. Of course, the first step toward using GLSL is to create a program that utilizes the OpenGL API. GLSL programs don't stand on their own; they must be a part of a larger OpenGL program. In this chapter, we will provide some tips and techniques for getting started. We'll cover how to load, compile, link, and export a GLSL shader program. First, let's start with some background.