Hooke's Law is a fundamental principle in physics that describes how materials stretch or compress when a force is applied. It states that the amount of deformation, or change in length, of an elastic material is directly proportional to the force applied to it, as long as the material's elastic limit is not exceeded. This means that if you pull on a spring, for example, it will stretch more if you pull harder. This law is named after the 17th-century scientist Robert Hooke, who first formulated it. Hooke's Law is essential in understanding how various materials behave under stress, and it is widely used in engineering and design to ensure that structures can withstand forces without breaking or deforming permanently.