Sergio Petrera is Senior Professor at the Gran Sasso Science Institute, Italy. He has been researcher at the italian Institute of Nuclear Physics (INFN) in Rome and Professor of Physics at Lecce and L'Aquila Universities. He has been INFN Director in Lecce and Director of the Physics Department in L'Aquila. Up until 1985 his research interests lay mainly in particle physics at accelerators, in several experiments at Fermilab and CERN, including the hybrid searches for charm in neutrino production and for beauty in hadro-production. Later on his interests have focused on astroparticle physics, including studies of cosmic rays, searches for monopoles, atmospheric neutrino oscillations, and neutrino bursts from stellar collapses in the experiment MACRO at Gran Sasso Laboratory. He is currently involved in the field of Ultra High Energy Cosmic Rays at the Pierre Auger Observatory in Argentina.

• I Problems.- 1 Nuclear Physics.- 2 Particle Physics.- 3 Experiments and detection methods.- II Solutions.- 4 Nuclear Physics.- 5 Particle Physics.- 6 Experiments and detection methods.

Sergio Petrera is Senior Professor at the Gran Sasso Science Institute, Italy. He has been researcher at the italian Institute of Nuclear Physics (INFN) in Rome and Professor of Physics at Lecce and L'Aquila Universities. He has been INFN Director in Lecce and Director of the Physics Department in L'Aquila. Up until 1985 his research interests lay mainly in particle physics at accelerators, in several experiments at Fermilab and CERN, including the hybrid searches for charm in neutrino production and for beauty in hadro-production. Later on his interests have focused on astroparticle physics, including studies of cosmic rays, searches for monopoles, atmospheric neutrino oscillations, and neutrino bursts from stellar collapses in the experiment MACRO at Gran Sasso Laboratory. He is currently involved in the field of Ultra High Energy Cosmic Rays at the Pierre Auger Observatory in Argentina.

• I Problems.- 1 Nuclear Physics.- 2 Particle Physics.- 3 Experiments and detection methods.- II Solutions.- 4 Nuclear Physics.- 5 Particle Physics.- 6 Experiments and detection methods.