  In recent years, the development of spectropolarimetric techniques deeply
modified our knowledge of stellar magnetism. In the case of solar-type stars,
the challenge is to measure a geometrically complex field and determine its
evolution over very different time frames. In this article, I summarize some
important observational results obtained in this field over the last two
decades and detail what they tell us about the dynamo processes that
orchestrate the activity of cool stars. I also discuss what we learn from such
observations about the ability of magnetic fields to affect the formation and
evolution of Sun-like stars. Finally, I evoke promising directions to be
explored in the coming years, thanks to the advent of a new generation of
instruments specifically designed to progress in this domain.
