I present a general family of dynamical models with simple analytical
potential-density pairs suited to modelling galactic bulges and nuclei
with double power-law radial density profiles and an optional central
black hole. Analytical expressions for the potential and velocity dis
persion of these models are given for the spherical case. Many previou
sly known analytical spherical models, including the recent gamma/eta-
models by Dehnen and Tremaine et al., are special cases of this family
. The family also forms a complete set for constructing general galaxy
models or solving Poisson's equation in the non-spherical case. In pa
rticular, a generalized Clutton-Brock and Hernquist-Ostriker orthogona
l basis set is given.