  During the past century Einstein's theory of General Relativity gave rise to
an experimental triumph, however, there are still aspects of this theory to be
measured or more accurately tested. One of the main challenges in experimental
gravitation, together with the direct detection of gravitational waves, is
today the accurate measurement of the gravitomagnetic field generated by the
angular momentum of a body. Here, after a description of frame-dragging and
gravitomagnetism and of the main experiments to detect these relativistic
phenomena, we show that the fundamental tests of General Relativity performed
by Lunar Laser Ranging do not, however, include a measurement of the intrinsic
gravitomagnetic field generated by the angular momentum of a body.
