  The interface between the bright solar surface and the million-degree corona
continues to hold the key to many unsolved problems in solar physics. Advances
in instrumentation now allow us to observe the dynamic structures of the solar
chromosphere down to less than 0.1" with cadences of just a few seconds and in
multiple polarisation states. Such observational progress has been matched by
the ever-increasing sophistication of numerical models, which have become
necessary to interpret the complex observations. With an emphasis on the quiet
Sun, I will review recent progress in the observation and modelling of the
chromosphere. Models have come a long way from 1D static atmospheres, but their
predictions still fail to reproduce several key observed features.
Nevertheless, they have given us invaluable insight into the physical processes
that energise the atmosphere. With more physics being added to models, the gap
between predictions and observations is narrowing. With the next generation of
solar observatories just around the corner, the big question is: will they
close the gap?
