We propose high resolution spectroscopic observations with the
 ISO satellite toward a number of unexplored Southern star-forming
 regions in order to determine their physical and chemical state.
 The chemical composition of the gas is strongly influenced by
 interaction with the dust, and is an excellent probe
 of the evolutionary stage of the object. Key molecules
 for observations are CO2, H2O, OH, C2H2, CH3 and CH4,
 none of which can be observed from the ground from a Southern
 hemisphere site. The data will provide insight into the
 amount of grain surface processing and the atomic hydrogen,
 carbon and/or oxygen content of the initial collapsing cloud. The
 excitation temperatures of the molecules will provide clues to the
 mechanism for returning molecules from the grains to
 the gas (thermal evaporation vs shock disruption of icy mantles).
 Detailed chemical modeling should allow accurate constraints
 on the time scales associated with these processes.
 Together with complementary ISO observations of solid state
 features proposed by others and our existing ground-based
 (sub)millimeter data, these observations will provide a unique
 data set of both the gas and the dust component for the same
 line of sight for a number of star forming regions.