This paper considers three general views about the nature of moral obligation and three particular answers concerning the following question: if on Monday you lend me a book that I promise to return to you by Friday, what precisely is my obligation to you and what constitutes its fulfillment? The example is borrowed from W.D. Ross, who in The Right and the Good proposed what he called the Objective View of obligation, from which he inferred what is here called the (...) First Answer to the question. In Foundations of Ethics Ross repudiated the Objective View in favor of the Subjective View, from which he inferred a Second Answer. In this paper each of the Objective and Subjective Views and the First and Second Answers are rejected in favor of the Prospective View and a Third Answer. The implications of the Prospective View for another question closely related to the original question are then investigated: what precisely is your right regarding my returning the book and what constitutes its satisfaction? (shrink)