  Orbital solutions for binary or multiple stellar systems that combine
astrometry (e.g., position angles and angular separations) with spectroscopy
(radial velocities) have important advantages over astrometric-only or
spectroscopic-only solutions. In many cases they allow the determination of the
absolute masses of the components, as well as the distance. Yet, these kinds of
combined solutions that use different types of observations in a global
least-squares fit are still not very common in the literature. An outline of
the procedure is presented, along with examples to illustrate the sort of
results that can be obtained. The same method can easily be extended to include
other types of measurements (times of eclipse, Hipparcos observations,
interferometric visibilities and closure phases, parallaxes, lunar
occultations, etc.), which often complement each other and strengthen the
solution.
