  The magnetic field of the Sun is generated by internal dynamo process with a
cyclic period of 11 years or a 22 year magnetic cycle. The signatures of the
Sun's magnetic cycle are observed in the different layers of its atmosphere and
in its internal layers. In this review, we use the same diagnostics to
understand the magnetic cycles of other stars with the same internal structure
as the Sun. We review what is currently known about mapping the surface
magnetic fields, chromospheric and coronal indicators, cycles in photometry and
asteroseismology. We conclude our review with an outlook for the future.
