Hot fragmentation of nuclei
  Today, we have a variety of reactions at hand that can be used to multi-fragment nuclei. In many of these reactions even several sources of fragments can be discerned and characterized.   There is overwhelming evidence that these sources of fragments are hot. It is already less clear whether heat by itself is sufficient to initiate the fragment decay. What causes fragmentation, and when and how are the fragments (pre)formed? These questions have remained as much a challenge as the complementary class of questions to which they are related: What observations derive their significance from the liquid-gas phase behavior of extended nuclear matter? And, can we observe a phase transition in finite nuclei?   Recent developments, largely coming from complex analyses of data sets measured in 4-pi-type experiments as well as from calculations based on advanced theoretical concepts, will be discussed. 
W. Trautmann (GSI) (for the ALADIN collaboration)