  We study the correlations between Supermassive Black Holes (BH) and their
host galaxies, using a sample of 83 BH masses collected from the most recent
and reliable spatially resolved estimates available from the literature. We
confirm the mono- and bivariate correlations between SMBHs and the bulges of
their host galaxies, confirming that the correlation with the effective
velocity dispersion is not significantly improved by higher dimensionality.
Instead, pseudobulges do not seem to correlate with their SMBHs, probably
because their secular evolution is often unable to trigger accretion onto the
central BH. We then present a novel approach aimed at finding the fundamental
relation between SMBHs and their host galaxies. For the first time, we
analytically combine BH masses with the Fundamental Plane (FP), showing that
Mbh-sigma_e appears to be the fundamental relation rather than a putative "BH
Fundamental Plane" of the kind Mbh-sigma_e-R_e. These results can be explained
by a picture which sees the Mbh-sigma_e relation as a natural outcome of the
change in AGN feedback from momentum- to energy-driven. The other scaling
relations are then established through the FP.
