  The Kepler space telescope has revolutionised our knowledge about exoplanets
and stars and is continuing to do so in the K2 mission. The exquisite
photometric precision, together with the long, uninterrupted observations
opened up a new way to investigate the structure and evolution of stars.
Asteroseismology, the study of stellar oscillations, allowed us to investigate
solar-like stars and to peer into the insides of red giants and massive stars.
But many discoveries have been made about classical variable stars too, ranging
from pulsators like Cepheids and RR Lyraes to eclipsing binary stars and
cataclysmic variables, and even supernovae. In this review, which is far from
an exhaustive summary of all results obtained with Kepler, we collected some of
the most interesting discoveries, and ponder on the role for amateur observers
in this golden era of stellar astrophysics.
