Isotopes of radiogenic and non-traditional stable elements have been extensively used for quantitative understanding of earth, planetary, ocean, and climatic processes. More recently, these applications have also been extended to medical, petroleum, forensic, and archaeological sciences. The proposed book aims at providing thorough analytical details for precise (ppm-level) isotopic measurements using state-of-the-art mass spectrometers (e.g., IRMS, TIMS, MC-ICPMS). All essential details on sample handling, chromatographic/solvent-extraction purification, isobaric interferences, spike-sample equilibration, data corrections, and measurement statistics for different isotopes have been reviewed here. It will also provide (i) information on recent technical analytical developments and (ii) “dos-and-donts� for analyzing isotopic ratios precisely. This book serves as an excellent handbook to set up these systematics with proper scientific rigor in academic and industrial laboratories.