  The goal of planet formation as a field of study is not only to provide the
understanding of how planets come into existence. It is also an
interdisciplinary bridge which links astronomy to geology and mineralogy.
Recent observations of young stars accompanied by their protoplanetary disks
(Manara et al. 2022) provide direct insights into the conditions at which
planets are forming. These astronomical observations can be taken as initial
conditions for the models of planet formation. In this chapter, we first give
an brief overview of key observational constraints for planet formation theory
derived from both the solar system and from the exoplanet population. We then
review physical mechanisms governing planetary system formation and discuss how
they can be put together to form global planet formation models. Finally, we
discuss how the compositional links from protoplanetary disks to planetary
atmospheres put novel constraints on planet formation theory. In particular, we
are currently gaining insights into the composition of the inner,
planet-forming region within the disks thanks to observations from the James
Webb Space Telescope (Grant et al. 2023; Perotti et al. 2023). The task for
planet formation modelling is then to link these observational properties and
compositional content to the physical properties, and also the elementary
inventory of meteorites, the Moon, Earth, and the other planets. If successful,
this global approach can provide useful constraints for geological studies.
