Delve into the intricacies of the stochastic gravitational wave background in this comprehensive lecture, the fourth in a series delivered by Angelo Ricciardone at the Galileo Galilei Institute. Explore advanced concepts and theories surrounding this fascinating aspect of gravitational wave astronomy over the course of 1 hour and 42 minutes. Gain insights into the latest research and developments in the field, enhancing your understanding of the cosmic microwave background and its implications for our understanding of the universe.