Moffat's work culminates in his nonsymmetric gravitational theory and scalar–tensor–vector gravity (now called MOG).

He proposes a variable speed of light approach to cosmological problems, which posits that G/c is constant through time, but G and c separately have not been.

In the weak-field approximation, STVG produces a Yukawa-like modification of the gravitational force due to a point source.

Intuitively, this result can be described as follows: far from a source gravity is stronger than the Newtonian prediction, but at shorter distances, it is counteracted by a repulsive fifth force due to the vector field.

The book was positively reviewed in EE Times, Physics World and Publishers Weekly.