Knowledge of scientific principles is also mandated as a result of a need to understand best and safest practice, especially in the use of ionising radiation where legislation, guidance and risk all form part of a medical specialist's pressures at work. It is no surprise therefore that radiologists are obliged to study and pass physics exams. Such exams can present a considerable challenge and the authors of this work recognise and sympathise with that challenge and have created a volume that is intended to be an educational resource and not just a pre-exam 'crammer'. Both authors have considerable experience in teaching, supporting and examining in medical science and have developed an awareness of where those sitting professional exams have traditionally struggled. This text is a distillation of that experience.