A plaintiff who voluntarily assumes a risk of harm cannot recover for the negligent or reckless conduct that causes the harm: that is known as assumption of risk. It is a complete defense. This lesson explores the defense, which together with contributory negligence has been part of negligence law for more than a century-and-a-half. The border between the two classic negligence defenses is sometimes confusing, so questions navigate the differences. Also, the lesson considers the continuing vitality of the defense of assumption of risk when contributory negligence is rapidly being replaced by comparative negligence.