This book provides an in-depth and systematic introduction to transmissibility-based system identification and its role in modern structural health monitoring (SHM). It establishes transmissibility as a paradigm-shifting framework for SHM, advancing beyond traditional input-output and output-only methods to propose a unified output-output paradigm. This innovative approach reduces reliance on excitation measurements or restrictive assumptions such as white noise inputs. Drawing on over 15 years of original research spanning more than 30 high-impact publications by the author, this work delivers new contributions ranging from theoretical advancements in transmissibility's physical/statistical properties to novel identification algorithms and practical SHM applications validated through numerical simulations, laboratory experiments, and field implementations. The detailed exposition of formulations and implementations empowers engineers to apply these concepts directly in practice, while researchers in academia and industry will find inspiration to pursue further investigations in SHM, including modal analysis, model updating, damage detection, influence line identification,and bridge weigh-in-motion, etc.
