  Here we introduce the interstellar dust modelling framework THEMIS (The
Heterogeneous dust Evolution Model for Interstellar Solids), which takes a
global view of dust and its evolution in response to the local conditions in
interstellar media. This approach is built upon a core model that was developed
to explain the dust extinction and emission in the diffuse interstellar medium.
The model was then further developed to self-consistently include the effects
of dust evolution in the transition to denser regions. The THEMIS approach is
under continuous development and currently we are extending the framework to
explore the implications of dust evolution in HII regions and the
photon-dominated regions associated with star formation. We provide links to
the THEMIS, DustEM and DustPedia websites where more information about the
model, its input data and applications can be found.
