Radioactive Decay and the Origin of Gamma and X-Radiation -- Interactions of Gamma Radiation with Matter -- Semiconductor Detectors for Gamma-Ray Spectrometry -- Electronics for Gamma-Ray Spectrometry -- Statistics of Counting -- Resolution: Origins and Control -- Spectrometer Calibration -- True Coincidence Summing -- Computer Analysis of Gamma-Ray Spectra -- Scintillation Spectrometry -- Choosing and Setting up a Detector, and Checking its Specifications -- Applications -- Low Count Rate Systems -- High Count Rate Systems -- Ensuring Quality in Gamma-Ray Spectrometry -- Gamma Spectrometry of Naturally Occurring Radioactive Materials (NORM) -- Troubleshooting -- Appendix A: Sources of Information -- Appendix B: Gamma- and X-Ray Standards for Detector Calibration -- Appendix C: X-Rays Routinely Found in Gamma Spectra -- Appendix D: Gamma-Ray Energies in the Detector Background and the Environment -- Appendix E: Chemical Names, Symbols and Relative Atomic Masses of the Elements.