Physical Techniques in Biological Research, Volume I: Optical Techniques focuses on improvements in physical techniques used in biological research on cells and tissues. The selection first discusses photochemistry and luminescence and light scattering, including applications of luminescence, theory of light scattering and its applications, and light scattering apparatus. The text then examines absorption spectroscopy, ultraviolet absorption spectrophotometry, and infrared spectrophotometry. Discussions focus on factors involved in data gathering, empirical correlation between molecular structure and absorption spectra, buffers for ultraviolet absorption spectrophotometry, instrumentation and techniques, and interpretation of data. The text ponders on the light microscope and phase and interference microscopy, as well as the optical and mechanical systems of microscopes; wave nature of light and its consequences; purposes of phase and interference microscopy; and principles of phase microscopy. The publication also reviews birefringence and dichroism and electron microscopy. The selection is highly recommended for students and readers interested in the physical techniques used in biological research.