Explore the fundamentals of stochastic processes in this comprehensive lecture delivered by Sanjib Sabhapandit at the International Centre for Theoretical Sciences. Delve into the advanced concepts of statistical physics as part of a pedagogical school aimed at bridging the gap between masters-level courses and cutting-edge research topics. Gain valuable insights from this 1 hour and 32 minute presentation, which serves as a preparatory lecture for Ph.D. students, post-doctoral fellows, and faculty members. Discover how this lecture fits into a broader program covering topics such as renormalization group theory, quantum critical phenomena, interacting particle systems, population genetics, and driven diffusive systems, all presented by renowned experts in the field.