Annual report of the Argonne National Laboratory Radiological and Environmental Research Division regarding activities related to molecular physics and chemistry. The papers in the present volume are ordered in accordance with the subjects treated. Papers 1-6 concern electron energy-loss spectroscopy; papers 7-24 photoabsorption, photoionization, and photoelectron analysis; papers 25-34 electron collisions and related topics; papers 35-36 the delivery of radiation energy to matter; and papers 37-40 energetic collisions of atoms and molecules.