  This chapter reviews the most recent advancements on the topic of terrestrial
and giant planet interiors, including Solar System and extrasolar objects.
Starting from an observed mass-radius diagram for known planets in the
Universe, we will discuss the various types of planets appearing in this
diagram and describe internal structures for each type. The review will
summarize the status of theoretical and experimental works performed in the
field of equation of states (EOS) for materials relevant to planetary interiors
and will address the main theoretical and experimental uncertainties and
challenges. It will discuss the impact of new EOS on interior structures and
bulk composition determination. We will discuss important dynamical processes
which strongly impact the interior and evolutionary properties of planets (e.g
plate tectonics, semiconvection) and describe non standard models recently
suggested for our giant planets. We will address the case of short-period,
strongly irradiated exoplanets and critically analyse some of the physical
mechanisms which have been suggested to explain their anomalously large radius.
