This course will focus on electromagnetic radiation and its interaction with atoms and molecules. The course will assume a general knowledge of quantum chemistry, (i.e., Chem 401), although a quick review of potential energy functions, wavefunctions, states, and quantization of energies will be given. We will cover first-principle concepts of Rotational Spectroscopy, Vibrational Spectroscopy, Electronic Spectroscopy, and Time-resolved Spectroscopy. In so doing, attention will be placed on developing intuition into the different quantum states and the transitions between them. Most of the information will center on diatomic molecules, although some examples of polyatomics will be given with emphasis placed on how structure is determined from spectra. The effects of the dynamics of molecules in varying states on spectral features will also be covered. The general features of the experimental methods implemented to record the associated spectra will be presented.