R. Decarli: "The mass of supermassive Black Holes" Abstract: I will summarize the different observational techniques adopted in order to estimate the mass of supermassive Black Holes. -- M.Cavadini: "The cooling functions" Abstract:I will review how different cooling functions apply to the gas dynamics in circomnuclear galactic disks. -- M. Dotti: "Massive Blach Hole binary dynamics in stellar and gaseous environments" Abstract: I will briefly summarize the dynamical evolution of massive black hole binaries driven by interactions with stars and gaseous disks in the nuclear regions of merging galaxies.