  The observation of high-energy extraterrestrial neutrinos is one of the most
promising future options to increase our knowledge on non-thermal processes in
the universe. Neutrinos are e.g. unavoidably produced in environments where
high-energy hadrons collide; in particular this almost certainly must be true
in the astrophysical accelerators of cosmic rays, which thus could be
identified unambiguously by sky observations in "neutrino light". To establish
neutrino astronomy beyond the detection of single events, neutrino telescopes
of km3 scale are needed. In order to obtain full sky coverage, a corresponding
detector in the Mediterranean Sea is required to complement the IceCube
experiment currently under construction at the South Pole. The groups pursuing
the current neutrino telescope projects in the Mediterranean Sea, ANTARES, NEMO
and NESTOR, have joined to prepare this future installation in a 3-year,
EU-funded Design Study named KM3NeT. This report will highlight some of the
physics issues to be addressed with the KM3NeT detector and will outline the
path towards its realisation, with a focus on the upcoming Design Study.

Astrophysics