Everyone faces pressure. Pressure can come from your boss to work late, from your friends to go partying, from your government to join the military, and from a mugger demanding your wallet or your life. The pressure can be from individuals, groups, and even society as a whole, as when millions of people spread stigma against those remaining unmarried, pressuring singles to marry, or when millions of voters support candidates rounding up migrants, pressuring these migrants to repatriate home. This is a book about when pressure--whether implicit or explicit, from individuals or groups--leads to invalid consent. Invalid consent occurs when someone's consent fails to dissolve another person's duty. For example, if a mugger holds you up at gunpoint and demands your money, and so you consent to hand it over, the mugger maintains a duty to not take your money, such that your consent is invalid. Yet, sometimes pressure--even quite explicit and deadly pressure--is perfectly compatible with valid consent. For example, if a refugee is held up gunpoint by a soldier demanding that he leave the country, and he consents to an aid worker smuggling him to safety, his consent to the aid worker seems valid: he makes it the case that the aid worker rescuing him violates no duty in carrying him across the border. The question, then, is why sometimes consent is valid despite extreme pressure, and other times it is not. To answer this question, we must pull apart different types of pressure, different duties people owe each other, and different rights people have when giving consent to others.