Negligence law hinges on the concept of breach of duty. This occurs when someone fails to meet the expected standard of care, potentially causing harm to others. Understanding breach of duty is crucial for determining liability in various situations, from car accidents to medical malpractice. The reasonable person test is a key tool in assessing breach of duty. It compares the defendant's actions to those of a hypothetical reasonable person in similar circumstances. Factors like foreseeability of harm, risk magnitude, and burden of precautions all play a role in determining if a breach occurred.