Errors in calculating drug dosages can cause significant harm to patients, particularly neonates, infants and children. Pharmacists are seen as a 'safety net' by fellow healthcare professionals. Therefore, it is essential that pharmacists fully understand pharmaceutical calculations. This book, written by pharmacy teachers, is an introduction to drug dosage and other pharmaceutical calculations. Each chapter contains learning objectives, numerous worked examples, as well as sample questions and answers. This revised and expanded edition includes a new chapter on accuracy of measurements, a new appendix on performing arithmetical routines, and updated worked examples.