We review the various techniques used to constrain the Galactic halo mass profile for radii \mathrel { \hbox to 0.0 pt { \lower 3.0 pt \hbox { $ \mathchar 536 $ } \hss } \raise 2.0 pt% \hbox { $ \mathchar 318 $ } } 20 kpc with particular emphasis on identifying a self-consistent halo model and resolving the apparent discrepancies present in the literature on this subject .
We collate published results and demonstrate that they are all consistent with a Galactic halo that is nearly isothermal with a characteristic velocity of 180 to 220 km sec ^ { -1 } and an extent \mathrel { \hbox to 0.0 pt { \lower 3.0 pt \hbox { $ \mathchar 536 $ } \hss } \raise 2.0 pt% \hbox { $ \mathchar 318 $ } } 200 kpc .