The ECCOMAS Thematic Conference Multibody Dynamics 2005 was held in Madrid, representing the second edition of a series which began in Lisbon 2003. The conference was held under the auspices of the European Community on Computational Methods in Applied Sciences ECCOMAS and provided a forum for discussion of several topics, through the participation of 161 researchers from 29 countries, mostly Europeans but also from Africa, America and Asia. This book contains the revised and extended versions of selected conference communications, representing the state-of-the-art in the advances on computational multibody models, from the most abstract mathematical developments to practical engineering applications. This book will be highly valuable for experienced researchers that want to keep updated on the details of the latest driving ideas in this field, but also to researchers approaching the field for the first time, since it provides a useful overview of the most active areas and the efforts devoted by many prominent research groups worldwide.