In "The Interior Castle", 16th century mystic St. Teresa of Avila guides the reader through a series of seven metaphorical mansions that represent the Christian seeker's relationship with God. Well--"guides" might be too strong of a word. In spite of the book's orderly premise, St. Teresa wanders all over the place. In each mansion, Teresa discusses different types of prayer belonging to different levels of spiritual advancement, the visions and/or feelings of spiritual union that accompany them, and how you can know whether such a vision and/or feeling comes from God or Satan. But Teresa switches back and forth between kinds of prayers and topics so frequently that by the third mansion I was wishing there were a Microsoft Powerpoint version with a clear, succinct outline and bullet points. By the end, I was zoning out for pages at a time.
This is also a hard read if you come from a liberal religious tradition. St. Teresa writes things like: "Let us, sisters, meditate on the infinite mercy and patience of God in not casting us down to hell at once, and let us render him hearty thanks. Surely we should be ashamed of resenting anything done or said against us--we, who are the scum of the earth, when we see what outrages are offered to God our Creator . . . by us His creatures; yet we are wounded whenever we hear an unkind word having been spoken of us." (p. 157) ...If you are willing to read through the layers of hellfire, brimstone, and sexism, there is some wisdom there.