A topology to equip the linear space ℒ(X, X, μ), which will turn it into a Banach space, is investigated in this chapter. Section 5.1 summarizes the basics on normed spaces that will be required in Chapter 5 as well as in parts of Chapters 6, 10, and 12. We assume the reader has been introduced to linear spaces (or vector spaces) before — see, e.g., Lemma 4.5.