  A review is given on the theory of metal-insulator transitions (MIT) in doped
semiconductors. We focus in particular on reviewing theories of their anomalous
magnetic properties, which emerge from the interplay of spin and charge
correlations and disorder.Building on the review of these existing theories and
experiments, we suggest that the finite temperature phase diagram can be
structured into 1. a random quantum spin liquid phase at subcritical doping and
low temperature, as described by the Bhatt-Lee theory of random spin clusters,
mostly random singlets. 2. a critical non-Fermi-liquid fan, originating at the
MIT, which is dominated by random Kondo singlets with a universal tail of the
distribution of their binding energies. This is caused by multifractality and
results in an anomalous power law divergence of the magnetic susceptibility
with a universal power and 3. a supercritical, low temperature phase. Rare
events caused by the random placement of dopants do not allow to define strict
phase boundaries. Remaining open problems are reveiwed and outlined. Finally,
the possibility of finite temperature delocalization transitions is reviewed,
which arcaused by the correlation induced temperature dependence of the spin
scattering rate from magnetic moments. This review article is devoted to the
memory of Konstantin B. Efetov.
