Book excerpt: Radioactive drug development is a multi-disciplinary task. Therefore, dedicated scientists and experts from different fields of specialisation have contributed to this book. The text reviews forty years of advances in radiopharmaceutical development based on Technetium. The first section reviews basic principles and analytic methods, and information on chemical makeup of radiopharmaceuticals. Part 2 reviews 99mTc-radiopharmaceuticals used in nuclear medicine, thoroughly outlining their chemistry, formulation, pharmacokinetics and clinical applications.