The document introduces composite functions, which are formed by placing one function inside another. To evaluate a composite function f(g(x)), the inner function g(x) is evaluated first, and the result is substituted into the outer function f(x). It provides examples of evaluating various composite functions step-by-step. Key concepts covered include working from the inside out, and that the composition f(g(x)) is not the same as the multiplication f * g(x). Homework problems are assigned.