  We review recent progress in point contact spectroscopy (PCS) to extract
spectroscopic information out of correlated electron materials, with the
emphasis on non-superconducting states. PCS has been used to detect bosonic
excitations in normal metals, where signatures (e.g. phonons) are usually less
than 1$\%$ of the measured conductance. In the superconducting state, point
contact Andreev reflection (PCAR) has been widely used to study properties of
the superconducting gap in various superconductors. In the last decade, there
have been more and more experimental results suggesting that the point contact
conductance could reveal new features associated with the unusual single
electron dynamics in non-superconducting states, shedding a new light on
exploring the nature of the competing phases in correlated materials. We will
summarize the theories for point contact spectroscopy developed from different
approaches and highlight these conceptual differences distinguishing point
contact spectroscopy from tunneling-based probes. Moreover, we will show how
the Schwinger-Kadanoff-Baym-Keldysh (SKBK) formalism together with the
appropriate modeling of the nano-scale point contacts randomly distributed
across the junction leads to the conclusion that the point contact conductance
is proportional to the {\it effective density of states}, a physical quantity
that can be computed if the electron self energy is known. The experimental
data on iron based superconductors and heavy fermion compounds will be analyzed
in this framework. These recent developments have extended the applicability of
point contact spectroscopy to correlated materials, which will help us achieve
a deeper understanding of the single electron dynamics in strongly correlated
systems.
