This exhaustively-researched, carefully-focused book asks whether imagination, emotion and art can enlighten our sense of right and wrong, looking at this question through the lens of moral philosophy with contributions from cognitive science, psychology and neurology. If moral thinking is simply logical reasoning or following God-given law, why did the poet Shelley say that "the great instrument of moral good is the imagination"? Why does ethical reasoning tend towards absolutes: something is either right or wrong, period, while a thoughtful minority values the "priority of the particular" - that unique aspects of a situation may come closer to the heart of the matter than any general rules could? Are emotions, as many philosophers in history have theorized, only a distraction from the clear perception of duty, or do feelings add something important, even critical, to how we judge good and bad, right and wrong? Can great works of art and literature embody imagination, the particular, and emotions to illuminate human life in ways crucial to ethical thinking?This book introduces an original idea in philosophy, "moral density," which for the first time elucidates the profound relation between art and ethics. Written for the literate layperson, an academic or technical background is not necessary, so this book will be of interest not only to philosophers and educators, but to all who are concerned with what is good, and how to see it and teach it.