  We give an overview of the light-front holographic approach to strongly
coupled QCD, whereby a confining gauge theory, quantized on the light front, is
mapped to a higher-dimensional anti de Sitter (AdS) space. The framework is
guided by the AdS/CFT correspondence incorporating a gravitational background
asymptotic to AdS space which encodes the salient properties of QCD, such as
the ultraviolet conformal limit at the AdS boundary at $z \to 0$, as well as
modifications of the geometry in the large $z$ infrared region to describe
confinement and linear Regge behavior. There are two equivalent procedures for
deriving the AdS/QCD equations of motion: one can start from the Hamiltonian
equation of motion in physical space time by studying the off-shell dynamics of
the bound state wavefunctions as a function of the invariant mass of the
constituents. To a first semiclassical approximation, where quantum loops and
quark masses are not included, this leads to a light-front Hamiltonian equation
which describes the bound state dynamics of light hadrons in terms of an
invariant impact variable $\zeta$ which measures the separation of the partons
within the hadron at equal light-front time. Alternatively, one can start from
the gravity side by studying the propagation of hadronic modes in a fixed
effective gravitational background. Both approaches are equivalent in the
semiclassical approximation. This allows us to identify the holographic
variable $z$ in AdS space with the impact variable $\zeta$. Light-front
holography thus allows a precise mapping of transition amplitudes from AdS to
physical space-time. The internal structure of hadrons is explicitly introduced
and the angular momentum of the constituents plays a key role.
