  My brief for the IAC Winter School was to cover observational results on
helioseismology, flagging where possible implications of those results for the
asteroseismic study of solar-type stars. My desire to make such links meant
that I concentrated largely upon results for low angular-degree (low-l) solar p
modes, in particular results derived from "Sun-as-a-star" observations (which
are of course most instructive for the transfer of experience from
helioseismology to asteroseismology). The lectures covered many aspects of
helioseismology - modern helioseismology is a diverse field. In these notes,
rather than discuss each aspect to a moderate level of detail, I have instead
made the decision to concentrate upon one theme, that of "sounding" the solar
activity cycle with helioseismology. I cover the topics from the lectures and I
also include some new material, relating both to the lecture topics and other
aspects I did not have time to cover. Implications for asteroseismology are
developed and discussed throughout.
