  The gravitational effects in the relativistic quantum mechanics are
investigated in a relativistically derived version of Heaviside's speculative
Gravity (in flat space-time) named here as Maxwellian Gravity. The standard
Dirac's approach to the intrinsic spin in the fields of Maxwellian Gravity
yields the gravitomagnetic moment of a Dirac (spin 1/2) particle exactly equals
to its intrinsic spin. Violation of The Equivalence Principle (both at
classical and quantum mechanical level) in the relativistic domain has also
been reported in this work.
