Theory of Spectroscopy, Excitation Relaxation Process, Principle, Instrumentation, Different Types of Instruments used in UV - Visible Spectroscopy and Applications of UV - Visible Spectroscopy, Types of ELectrons, Different Types of Electronic Transitions, Beer-Lambart's Law, Deviations from Beer-Labart's Law, Isobestic Point, Bathochromic Shift, Hypsochromic Shift, Hyper Chromic Effect, Hypo Chromic Effect, Chromogenic Agent.