  We propose a general theory of the spin-transfer effects that occur when
current flows through inhomogeneous magnetic systems. Our theory does not rest
on an appeal to conservation of total spin, can assess whether or not
current-induced magnetization precession and switching in a particular geometry
will occur coherently, and can estimate the efficacy of spin-transfer when
spin-orbit interactions are present. We illustrate our theory by applying it to
a toy-model two-dimensional-electron-gas ferromagnet with Rashba spin-orbit
interactions.
