After the general introduction chapter, which covered the properties of uranium and its main compounds and an overview of analytical techniques, a myriad of analytical procedures used for characterization of uranium were presented in Chapters 2 through 5. This large variety reects the diversity of samples in which uranium has to be determined. On the one hand, there are the samples in which uranium is the major constituent, as expressed in Chapter 2, which described the nuclear fuel cycle, and the focus is on determining the level of impurities in the nuclear grade materials. A unique analytical challenge involves the characterization of highly radioactive samples like those encountered in spent nuclear fuel (after irradiation in a reactor). On the other hand, there are environmental samples that include soil, sediments, plants, water bodies, and air samples, in which uranium is present at low levels, usually in the parts-per-million to parts-per-billion range. In addition, there are biological samples, mainly of urine, feces, hair, and nails, in which uranium is present at trace level concentrations, usually in the parts-per-billion to parts-per-trillion range. For nuclear forensics and safeguards applications, uranium-bearing particles need to be detected and located prior to characterization according to their physical, chemical, and elemental properties. The isotopic composition of uranium is an essential feature of uranium characterization throughout this monograph.