I think you can perform a close reading on any self-contained unit, and at least in my experience, close readings are usually performed on smaller units of text, because they pay very close attention to the specific language used in a text in order to build a larger interpretation of what the text means.

In this case, the self-contained unit I chose to examine was the prologue. However, it seems like my mentioning that this was “just from the first four pages” wasn’t a clear enough signpost that I was just reading the prologue. I’ll be more clear in the future about exactly what I’m up to.