This book provides a detailed overview of multifunctional sensors, covering discussions on different types of multifunctional sensors developed in past years. As a case study, the development of admittance-type multifunctional sensors is provided, constituting its construction, working principles, measurements, and instrumentation used. It also explores a review of the research in the field from 1990 to 2022. It will be a useful resource for researchers of sensor technologies across physics, engineering, and other physical sciences.