The study of calculus is basically divided into two parts: differentiation and integration. We've already covered how to differentiate functions of several variables and the interpretation of this. Now we move on to integration in several variables. As you'll see, this is a very full topic. Essentially the rest of the course is on integration. There are many different ways to integrate, depending on whether the integrand is a scalar function or a vector field. In this chapter, we'll stick with scalar functions of several variables.