Experimental microdosimetry deals with the measurement of charged particle energy deposition in tissue equivalent volumes, ranging in size from nanometres to micrometres. Microdosimetry is employed to improve our understanding of the relationship between radiation energy deposition, the resulting biological effects, and the appropriate quantities to be used in characterizing and quantifying radiation quality. Although many reviews and contributions to the field have been published over the past fifty years, this new book is the first to provide a single, up to date, and easily accessible account of experimental microdosimetry. This book is designed to be used in medical, radiation, and health physics courses and by Master’s and PhD students. In addition to serving as an introductory text to the field for graduate students, this book will also be of interest as a teaching and reference resource for graduate supervisors and established researchers. Drs. Lennart Lindborg and Anthony Waker have spent a life-time career in experimental microdosimetry research in academic, industrial and regulatory environments and have observed the development of the field from its early days as a recognized discipline; they bring to this book particular knowledge and experience in the design, construction, operation and use of tissue equivalent gas ionization counters and chambers.