The paragraph is the unit of scholarly composition. Scholars “compose themselves” in paragraphs of, generally speaking, at least six sentences and at most two-hundred words. Each paragraph says one thing in its “key sentence” and supports, elaborates or defends it with the rest. In each posture, it addresses the difficulty the reader presumably experiences when facing the claim it is making. If the reader finds the claim hard to believe, the paragraph must support it with evidence. If the reader finds the claim hard to understand, the paragraph must elaborate its meaning. If the reader finds the claim hard to agree with, the paragraph must defend it against the reader’s objections. Notice that in each case, we answer the question “How shall I write this paragraph?” by asking another: “Who is reading this paragraph?” Or, better, we ask: “What does the reader know?