  Coherence of spins of electrons confined in III-V quantum dots is strongly
affected by their hyperfine interaction with the nuclei. In this paper an
introduction to this subject will be given. Some theoretical approaches to the
problem will be outlined. Most attention will be given to the Quasi-Static Bath
Approximation, to the cluster expansion theories of dephasing due to the
nuclear dynamics induced by the dipolar interactions (spectral diffusion), and
to the effective Hamiltonian based theory of dephasing due to
hyperfine-mediated interactions. The connections between the theoretical
results and various experiments will be emphasized.
