Explore Feynman's path integral formulation of quantum mechanics in this 26-minute video lecture. Delve into the innovative approach developed by Richard Feynman in the 1940s, which describes quantum particle motion as a sum over all possible trajectories. Learn how classical mechanics emerges from this quantum description, understanding the concept of the path of stationary action. Examine the double-slit experiment, gain intuitive insights into Feynman's sum over paths, and discover the connection between quantum mechanics and Lagrangian mechanics. Uncover the story behind Feynman's groundbreaking work and prepare for future discussions on computing the path integral.