Delve into the physics of supermassive black holes in this comprehensive lecture aimed at graduate students. Explore current theories on the formation of seed black holes, accretion processes driving their growth, and the impact on their surrounding environment. Learn about modeling techniques including analytic, numerical, and semi-empirical approaches guided by observational data. Examine accretion disc structure, thin accretion discs, viscosity, and disc timescales. Investigate the Eddington limit, super-Eddington accretion, and the cosmological picture of black hole growth. Discover the relationship between galaxies and their central supermassive black holes, active galactic nuclei (AGN) spectra, and jet formation. Analyze black hole scaling relations and trace the globally averaged black hole accretion rate over cosmic time. Conclude with a discussion of current open questions in black hole physics and participate in a Q&A session.