This publication, Fracture Mechanics, contains papers presented at the Eleventh National Symposium on Fracture Mechanics which was held 12-14 June 1978 at Virginia Polytechnic Institute and State University, Blacksburg, Va. The American Society for Testing and Materials' Committee E24 on Fracture Testing of Metals sponsored the symposium. C. W. Smith, Virginia Polytechnic Institute and State University, served as editor of this publication.