The second workshop on High Energy Astrophysics of the Ma..x-Planck-Society and the Academia Sinica was held at Ringberg Castle near Tegernsee during the week July 12-July 17, 1987. It is the purpose of these workshops to en courage the exchange of ideas between German and Chinese astrophysicists (scientists from other countries are also welcome, of course), and the pleas ant atmosphere and surroundings of Ringberg Castle certainly helped the development of relaxed and stimulating discussions. In addition, we seemed to have picked out the one week of perfect weather during a rainy summer....