The study of growth and characterization of single crystals is receiving increasing attention due to their various applications in solid state technology and laser technology. Single crystals are the fundamental building blocks for modern technology. Growth of crystals by gel method is a promising technique for growing single crystals. In recent years, iodates of alkali, transition, and alkaline earth metals have received great interest for investigations of their crystallographic, optical, and magnetic properties. Studies on growth and characterization of undoped and doped calcium iodate, barium iodate, and cadmium iodate by gel method and lithium iodate by solution method have been described in this book. These crystals are characterized by EDAX, XRD, FTIR, TGA, DTA, and DSC techniques.These techniques are described here in detail. Structural, thermal, magnetic, electrical, microtopographical and nonlinear optical properties are studied and described. Comparative study of all four types of crystals is also carried out.