This book was developed under 7FP ENETRAP II and covers the radiation protection knowledge requirements specified in Module 1 of the European Radiation Protection Training Scheme. It contains the theoretical background of radiation protection principles and invites the learner to implement the acquired knowledge in daily work situations via exercises. An e-book complements the text book and provides continuously updated exercises and simulations of practical situations where the RPE must be able to provide advice on the radiation protection measures to be taken.