Supermassive black holes (SMBHs) seem to be ubiquitous at the center of all galaxies which have been observed with high enough sensitivity with HST. SMBH masses are tightly linked with the masses and velocity dispersions of their host galaxies. Also, SMBHs are considered to be the central engines of active galactic nuclei (AGN). It is however still unclear how SMBHs have grown and if they have co-evolved with their hosts. In my talk I will derive, in ways independent of specific models, constraints on how SMBHs must have evolved within their dark matter halos. I will describe the accretion history of SMBHs from z≈6 to z≈0 by interconnecting a variety of data sets, including the AGN luminosity function, their clustering properties, and Eddington ratio distributions. I’ll show results obtained through a novel numerical code which evolves the SMBH mass function and clustering adopting broad distributions of Eddington ratios. I will finally insert SMBH evolution in a wider cosmological framework for galaxy evolution constrained directly from the Sloan Digital Sky Survey Data.