This introductory book: Introduction to Ionizing Radiation Measurements, Quantities, Protection and Some Radiological Parameters, is written for undergraduate and postgraduate students in the fields of Environmental, Radiation and Health Physics, Medical Physics, Radiation Biology and Biophysics. It promises to be a useful text book and companion for undergraduate students, postgraduate students as well as lecturers in aforementioned fields who wish to write academic manuscripts/papers for publications and make progress on their career ladder.