The intermediate species present in laser ablation plumes, particularly those formed during pulsed laser deposition (PLD) of thin films, have been identified for a variety of advanced materials systems. Optical multichannel analysis spectroscopy has been used to monitor the atomic and ionic species present, via their spectral emissions. Molecular beam-sampling mass spectrometry has been used to monitor the molecular species present, in addition to atoms and ions. With both monitoring approaches, temporal and spatial species distribution information has been obtained. Velocity distributions, obtained from the time-dependent mass spectral studies, show the effects of isentropic expansion to be predominant when compared with gasdynamic models of the plume evolution process. Also, the plume structure was found to be particularly sensitive to target elemental distribution. Examples of systems studied include high temperature superconductors, refractory compounds, ferroelectrics and nanostructured magnetic films.