Sr
2RuO
4 and the high-T
c cuprates are highly 2-dimensional metals with similar crystal st
ructures which transform into unconventional superconductors. In Sr
2RuO
4 p-wave superconductivity arises at a low temperature (T
c 1.5K) out of a well formed Landau-Fermi liquid. This behavior contrasts strongly with the high T
c and anomalous normal state of the cuprates and sharpens the question, what is so special about the cuprates? A key distinguishing feature is the existence of Umklapp electron-electron scattering processes near the saddle points of the single band cuprate Fermi surface-processes which are not allowed on the multi-band
ruthenate surface. These U-processes are responsible for the Mott charge gap at stoichiometry. In the case of the 2-leg ladder they reinforce pairing and lead to the
RVB insulating spin liquid at half-filling. A key question then is whether similar effects can occur in 2-dimensions leading to a partial t
runcation of the Fermi surface near the saddle points without broken translational symmetry. Scattering in the Cooper channel between the open and t
runcated pasts of the Fermi surface would then be responsible for the high-T
c superconductivity. The results of 1-loop RG investigations of a 2-patch model, restricted to the neighborhoods of the saddle points, and of a multi-patch model of the full Fermi surface are promising.