The book "IUTAM Symposium on Mesoscopic Dynamics of Fracture Process and Materials Strength" documents the contributions of the symposium that took place in July 2003 in Osaka, Japan. The aim of the symposium was to promote a focused discussion on the understanding of fracture processes and inhomogeneous deformation that influence material strength. The emphasis is on the mesoscopic dynamics associated with the evolutionary mechanical behavior interacting between micro and macro levels. The event attracted 66 participants from eight countries and included 42 presentations covering a wide range of fundamental topics in physics, mechanical models, computer-based strategies, and engineering applications. Topics addressed include, among others, the pattern formation of dislocations, crystalline plasticity, and the characteristic fracture of amorphous and nanocrystalline materials. This collection of works provides valuable insights into current developments and challenges in the research on mesoscopic dynamics.