This lecture covers the fundamentals of material fatigue, including the distinction between low-cycle and high-cycle fatigue, the Wöhler curve construction, endurance limit determination, and the effects of stress amplitude and mean stress on fatigue life. It also delves into the impact of pre-existing cracks on material fatigue, the Miner's rule for variable amplitude loading, and the Paris law for crack growth. Real-world examples of fatigue failures and the importance of understanding fatigue in engineering applications are highlighted.