  The study of solar neutrinos has given since ever a fundamental contribution
both to astroparticle and to elementary particle physics, offering an ideal
test of solar models and offering at the same time relevant indications on the
fundamental interactions among particles. After reviewing the striking results
of the last two decades, which were determinant to solve the long standing
solar neutrino puzzle and refine the Standard Solar Model, we focus our
attention on the more recent results in this field and on the experiments
presently running or planned for the near future. The main focus at the moment
is to improve the knowledge of the mass and mixing pattern and especially to
study in detail the lowest energy part of the spectrum, which represents most
of solar neutrino spectrum but is still a partially unexplored realm. We
discuss this research project and the way in which present and future
experiments could contribute to make the theoretical framemork more complete
and stable, understanding the origin of some "anomalies" that seem to emerge
from the data and contributing to answer some present questions, like the exact
mechanism of the vacuum to matter transition and the solution of the so called
solar metallicity problem.
