  In this paper I shall consider various possible scalar-vector-tensor field
theories which might be used to describe the Universe. After imposing numerous
constraints of a physical and mathematical nature on the theories under
consideration, we shall see that there still exists a plethora of viable
theories from which to choose. But hopefully I shall be able to convince you
that a scalar-vector-tensor field theory involving five scalar fields provides
a promising cosmological model. The advantage of this theory is that there is
no energy-momentum tensor for the matter fields, nor arbitrary functions, only
dimensionless constants, that need to be determined. I shall also construct the
most general multiple-scalar-vector-tensor field theory which is dimensionally
consistent and free of dimensioned constants. It turns out that this field
theory yields second-order field equations.
