It's especially helpful for you to read this chapter before the class meetings.
Spectroscopy is the basis of most astrophysics and most active research in astronomy.
Understanding fully almost any modern observation requires an understanding of the contents of this chapter. Chapter 4 is well written from the point of view of thoroughness at explaining theoretical details often glossed over in introductory texts, like why the sun has weak hydrogen lines in its spectrum even though it's mostly made up of hydrogen. On the other hand, Chapter 4 is oversimplified in the way it illustrates spectroscopes and in its presentation of the Bohr theory of the hydrogen atom. Furthermore, it doesn't have the specific astronomical examples that I like to present. In class, we'll cover real spectroscopes and real observations made at Colby's Collins Observatory.