"Is anything objectively evil? Is anything objectively good? How does what is evil differ from what is good? Can there be evil without good? Does evil have a cause? Does goodness have a cause? Do people have freedom of choice? Or is what they do always outside their control? If people can act freely, under what conditions can they be rightly thought to be responsible for what they do? And how is their behavior to be evaluated and explained? Is there such a thing as sin? If so, what is it? And how does it arise? Does it admit degrees? Does it come from what is not human? Or does its source lie wholly in us? These are questions that Aquinas discussed at various times in his life. But he was especially concerned with them when completing his Disputed Question De Malo (On Evil)... this work represents some of Aquinas's most mature thinking on goodness, badness, and human agency."--from the Preface.