This lecture covers the development of cryo-electron microscopy techniques for studying protein fibrillar aggregation, focusing on a-synuclein in neurodegenerative diseases like Parkinson's. It explains the wave-particle dualism, electron microscopy methods, and the resolution revolution in cryo-EM. The instructor discusses the structure determination pipeline, cryo-EM applications, and the impact of cryo-EM on understanding neurodegenerative diseases.