Book excerpt: The existence of rapid and even catastrophic turnovers within the Phanerozoic ecosystems has been discussed controversially for more than 170 years. Since 1980 this discussion has become even more intensive after the hypothesis of Alvarez, explaining the end-Cretaceous mass extinction as the result of a huge asteroid impact on the Earth. This theory stimulated several thousand papers and is still controversial. The international research programme on "Global Biological Events in Earth History" attempts to bring the discussion back to the facts by using multidisciplinary investigations of the major Phanerozoic events. The results of an international group of experts are presented giving a wealth of information and a thorough discussion of the causes of the various global events.