  The standard method of modelling axisymmetric stellar systems begins from the
assumption that mass follows light. The gravitational potential is then derived
from the luminosity distribution, and a unique two-integral distribution
function f(E,Lz) that generates the stellar density in this potential is found.
We show that the gravitational potential can instead be generated directly from
the velocity data in a two-integral galaxy, thus allowing one to drop the
assumption that mass follows light. The rotational velocity field can also be
recovered in a model-independent way. We present regularized algorithms for
carrying out the inversions and test them by application to pseudo-data from a
family of oblate models.
