  In the past two decades, the density matrix renormalization group (DMRG) has
emerged as an innovative new method in quantum chemistry relying on a
theoretical framework very different from that of traditional electronic
structure approaches. The development of the quantum chemical DMRG has been
remarkably fast: it has already become one of the reference approaches for
large-scale multiconfigurational calculations. This perspective discusses the
major features of DMRG, highlighting its strengths and weaknesses also in
comparison to other novel approaches. The method is presented following its
historical development, starting from its original formulation up to its most
recent applications. Possible routes to recover dynamical correlation are
discussed in detail. Emerging new fields of applications of DMRG are explored,
in particular its time-dependent formulation and the application to vibrational
spectroscopy.
