This course will cover the interaction of light with biological molecules and the use of light to analyze and quantitate molecules and molecular systems. Particular emphasis will be given to absorption and fluorescence spectroscopy in the ultra-violet and visible spectral range to study biomolecules and molecules of interest in pharmaceutical development. The use of fluorescence methods to obtain knowledge of molecular size and motion will be discussed as well as the application of these methods in fluorescence microscopy. The use of circular dichroism spectroscopy to study the conformation and conformational transitions of proteins, DNA, and other molecules will also be presented.