The work presented in the Book entitled “An approach to Study of Thiosemicarbazone And their transition metal complexes” can be summarizes the preparation and structure characterization of various thiosemicarbazones attached pyrazol aldehyde as well as their metal complexes. Synthesized ligands and metal complexes were characterized by different technique like mass, IR, 1H NMR, 13C NMR, UV-Visible spectroscopy as well as elemental analysis. The most important bands in the infrared spectra of the Copper(II), Nickel(II) and Cobalt(II) complex of thiosemicarbazone are along within their tentative assignment. The position of these bands was helpful to detect the bonding sites of all ligand molecules interacted with metal. In principle, the ligand can exhibit thione-thiol tautomerism since it contains a thioamide NH-C=S functional group.