  We describe an infinite family of quiver gauge theories that are AdS/CFT dual
to a corresponding class of explicit horizon Sasaki-Einstein manifolds. The
quivers may be obtained from a family of orbifold theories by a simple
iterative procedure. A key aspect in their construction relies on the global
symmetry which is dual to the isometry of the manifolds. For an arbitrary such
quiver we compute the exact R-charges of the fields in the IR by applying
a-maximization. The values we obtain are generically quadratic irrational
numbers and agree perfectly with the central charges and baryon charges
computed from the family of metrics using the AdS/CFT correspondence. These
results open the way for a systematic study of the quiver gauge theories and
their dual geometries.
