This book bridges the gap between physical foundations and medical applications of the NMR and MRI technologies, making them accessible to both physicists and biomedical scientists. The physical basis of these technologies is discussed in a manner that can be easily understood by scientists from different backgrounds, aiding them in gaining a clearer understanding of the subject. For instance, the medical applications of NMR and MRI technologies are described in a way that is accessible to physicists. Moreover, geometrical descriptions and specific mathematical tools are used to facilitate the visualizations of many concepts. Furthermore, the book covers modern technologies such as hyperpolarization and several other state-of-the-art techniques, along with their foundations.