Coherent anti-Stokes Raman scattering spectroscopy (CARS) is a new technique for obtaining Raman spectra with a high signal to noise ratio with greatly reduced sample damage and a discrimination against fluorescence of at least 10 to the 9th power. This technique is ideally suited as a method for obtaining resonance enhanced Raman spectra of biological macromoleucles which contain chromophores which absorb in the visible or UV region. It has been demonstrated that high quality spectra can be obtained with concentrations of 10 to the minus 3rd power M will be adequate in many cases. Only 1 to 5 milliwatts of average power are necessary and thus sample damage is minimal. Fluorescence is completely eliminated, making it possible to obtain CARS spectra of systems which cannot be studied by the spontaneous Raman effect. Recent advances in laser technology now make it possible to extend resonance CARS experiments into the ultraviolet so that nucleic acids and aromatic amino acids in proteins may be studied. The tuning range of the laser hardware proposed for this study is 2300 A to about 1.64 microns with no gaps and with high power levels. The objective of this study is the development of CARS as a practical biophysical technique. Initial emphasis will be placed on practical consequences of the complex nature of the third order susceptibility near an electronic resonance, e.g., optimum concentrations and excitation wavelengths. The unique UV capability of this spectrometer will be combined with the fluorescence rejection power of CARS in a study of resonance enhanced CARS spectra of aromatic amino groups in proteins.