Book excerpt: This volume contains the research papers presented at the 12th Eurographics Workshop on Computer Animation and Simulation, Manchester, UK, September 2-3, 2001. The workshop is an international forum for research in computer-animation and simulation. This year, we choose to give a special focus on the modelling and animation of complex phenomena. This includes the modelling of virtual creature- from their body-parts to the control of their behavior, and the animation of natural phenomena such as water, smoke, fire and vegetation. The call for papers required submission of the full papers for review, and each paper was reviewed by at least 2 members of the international program committee and additional reviewers. Based on the reviews, 16 papers were accepted. We added to the final program an invited talk by Jos Stam. We wish to thank all reviewers for their time and effort in working within the rigid constraints of the tight schedule, thereby making it possible to publish this volume in time for the workshop. We also thank the authors for their contributions to the workshop, without whom this unique forum for animation and simulation work would not exist.