Time-domain Studies of M31
  M31, our closest neighboring galaxy, is a stepping stone to studies of
stellar evolution, star formation, galaxy evolution, and cosmology. However,
due to the difficulties of performing photometry in such crowded fields and the
lack of wide cameras to encompass the entire galaxy, there has not been a
complete census of the stellar contents of M31. The advent of wide-field camera
provides us a unique opportunity to have a complete view of our neighboring
galaxy, enabling an inventory of its variable content. We present a review of
recent progresses of wide-field, high cadence surveys of M31, covering
different population of variables and transients. We also outline future
studies enabled by on-going and up-coming facilities.
