Explore the fundamental question of statistical mechanics in this 47-minute lecture on quantum thermalization. Delve into recent experimental advances allowing observation of isolated quantum systems under unitary time evolution. Examine the eigenstate thermalization hypothesis as a potential explanation for thermalization in nonintegrable Hamiltonian systems. Review recent progress in understanding quantum thermalization, covering topics such as experimental studies, quantitative analysis, energy identity, and fluctuations. Gain insights into promising unresolved areas for future research. Conclude with a discussion on the implications of these findings and participate in a question-and-answer session to deepen your understanding of quantum systems and their thermalization processes.