  A review of solar cycle prediction methods and their performance is given,
including early forecasts for cycle 25. The review focuses on those aspects of
the solar cycle prediction problem that have a bearing on dynamo theory. The
scope of the review is further restricted to the issue of predicting the
amplitude (and optionally the epoch) of an upcoming solar maximum no later than
right after the start of the given cycle. In their overall performance during
the course of the last few solar cycles, precursor methods have clearly been
superior to extrapolation methods. One method that has yielded predictions
consistently in the right range during the past few solar cycles is the polar
field precursor. Nevertheless, some extrapolation methods may still be worth
further study. Model based forecasts are quickly coming into their own, and,
despite not having a long proven record, their predictions are received with
increasing confidence by the community.

Solar and Stellar Astrophysics