  Geo-neutrinos, electron antineutrinos from natural radioactive decays inside
the Earth, bring to the surface unique information about our planet. The new
techniques in neutrino detection opened a door into a completely new
inter-disciplinary field of Neutrino Geoscience. We give here a broad
geological introduction highlighting the points where the geo-neutrino
measurements can give substantial new insights. The status-of-art of this field
is overviewed, including a description of the latest experimental results from
KamLAND and Borexino experiments and their first geological implications. We
performed a new combined Borexino and KamLAND analysis in terms of the
extraction of the mantle geo-neutrino signal and the limits on the Earth's
radiogenic heat power. The perspectives and the future projects having
geo-neutrinos among their scientific goals are also discussed.
