The Sun's global oscillations, which are studied both in spatially
unresolved ("Sun-as-a-star") and resolved observations of the solar
disk, have enabled helioseismology to probe in detail the solar
interior. I review firstly what is learned from the unresolved
measurements, since this gives an idea of what we may
in the not too distant future be able to learn about the interiors
of other stars undergoing solar-type oscillations. I then look at
the main results from resolved observations, which have begun to
reveal the structure and dynamics of the interior of a star in
exquisite detail.