An experimental and theoretical investigation of a flame/wall interface is presented to help understand the phenomenon of one-wall quenching. Special slot burners were designed to permit high spatial resolution, laser probing of the flame/wall interface, often referred to as the wall quench zone. Laser Raman spectroscopy and veiocimetry measurements of the fuel, temperature, and velocity in the flame/wall interface region show that the fuel is consumed rapidly (<5 ms) in spite of the low (~ 1000 K) temperature. Flame ionization detector measurememts ments confirm the absence of exhaust hydrocarbon from these premixed, laminar flames. Measurements of OH near the wall, taken together with a theoretical study of combusting flows for the burner geometry, identify species diffusion of fuel and radicals as the important process in the fuel decay. Relative flame-wall motion was shown to have only a weak influence on the results. These conclusions suggest that one-wall quenching in homogeneous change, S.I. engines is not a likely source for exhaust hydrocarbons.