Is it possible to apply a theoretical approach to ethics? The French philosopher Catherine Chalier addresses this question with an unusual combination of traditional ethics and continental philosophy. In a powerful argument for the necessity of moral reflection, Chalier counters the notion that morality can be derived from theoretical knowledge.Chalier analyzes the positions of two great moral philosophers, Kant and Levinas. While both are critical of an ethics founded on knowledge, their criticisms spring from distinctly different points of view. Chalier reexamines their conclusions, pitting Levinas against (and with) Kant, to interrogate the very foundations of moral philosophy and moral imperatives. She provides a clear, systematic comparison of their positions on essential ideas such as free will, happiness, freedom, and evil. Although based on a close and elegant presentation of Kant and Levinas, Chalier’s book serves as a context for the development of the author’s own reflections on the question “What am I supposed to do?” and its continued importance for contemporary philosophy.