  A review of recent developments of the dispersive optical model (DOM) is
presented. Starting from the original work of Mahaux and Sartor, several
necessary steps are developed and illustrated which increase the scope of the
DOM allowing its interpretation as generating an experimentally constrained
functional form of the nucleon self-energy. The method could therefore be
renamed as the dispersive self-energy method.
  The aforementioned steps include the introduction of simultaneous fits of
data for chains of isotopes or isotones allowing a data-driven extrapolation
for the prediction of scattering cross sections and level properties in the
direction of the respective drip lines. In addition, the energy domain for data
was enlarged to include results up to 200 MeV where available. An important
application of this work was implemented by employing these DOM potentials to
the analysis of the (\textit{d,p}) transfer reaction using the adiabatic
distorted wave approximation (ADWA).
  We review the fully non-local DOM potential fitted to ${}^{40}$Ca where
elastic-scattering data, level information, particle number, charge density and
high-momentum-removal $(e,e'p)$ cross sections obtained at Jefferson Lab were
included in the analysis. An important consequence of this new analysis is the
finding that the spectroscopic factor for the removal of valence protons in
this nucleus comes out larger by about 0.15 than the results obtained from the
NIKHEF analysis of their $(e,e'p)$ data. Another important consequence of this
analysis is that it can shed light on the relative importance of two-body and
three-body interactions as far as their contribution to the energy of the
ground state is concerned through application of the energy sum rule.
