Lanthanides open a new age in the modern era of Science. Because of its various coordination numbers, available of absorption spectra in easily accessible spectral regions and highly radioactive nature, lanthanides play immersing role in Biochemistry & Diagnostic fields. The book comprises of Seven Chapters. First one articulates the general features of lanthanides. Second chapter has focused on the coordination chemistry of lanthanides referring to its biologically significance. Chapter 3&4 discuss on its diagnostic approach as well as use as MRI agents. Chapter 5 explains the role of Lanthanide complexes as Shiff agent in whole organ systems. Chapter 5&6 elaborate the various forms of its clinical applications. The book will be immensely helpful academically, for the research scholars in perusing advanced research works.