This book investigates the substructuring technology in structural health monitoring (SHM) to improve the accuracy and efficiency of the present SHM methods. SHM has been developed for monitoring, evaluation, and maintenance of civil structures. As the civil structures are usually large scale and a large number of sensors are deployed on a structure, accurate evaluation and maintenance of civil structures are always time-consuming. The book establishes a fundamental framework of substructuring method for the fast analysis of finite element (FE) model and monitoring data. Several practical civil structures are used for illustration. The book is intended for undergraduate and graduate students who are interested in SHM technology, researchers investigating the accurate, efficient, and effective methods in SHM field, and engineers working on evaluation and maintenance of civil structures or other structural dynamics applications.