SCIENTIFIC ABSTRACT We propose to carry out high spectral resolution observations of atomic and molecular lines from the outflows around a number of cool evolved objects. These observations will address the following questions: (a) Can direct observational evidence be provided for the first time showing the operation of the proposed IR radiative pump mechanism for OH maser emission? (b) What is the abundance of H2O in O-rich winds? It has been proposed that OH originates mainly from H2O dissociation and, further, that H2O can be an important coolant in such winds. OBSERVATION SUMMARY We will use the SWS Fabry-Perot to observe the 34.6um doublet, which should be in absorption, as it is believed to pump the observed OH maser lines in the microwave region. The LWS Fabry-Perots will be used to observe seven OH doublets at 48.76um, 53.31um, 79.15um, 96.34um, 98.73um, 119.34um and 163.26um which are predicted to be part of the resulting emission cascade which leads to the inversion of the OH ground state. The SWS and LWS observations will be tied as closely together in time as possible for each target, due to the known strong variability of the OH masers. LWS FP observations will also be obtained at the wavelengths of three H2O rotational lines, at 108.07um, 136.50um and 179.53um, whose fluxes are predicted to be detectable from a number of objects, in an effort to diagnose how important H2O is as a coolant in the outflows. If targets in the Orion-hole should be observable (i.e. a Spring launch), the total amount of LWS Guaranteed (spacecraft) time allocated will be 19.86 hours, of which 7.51 hours will be for Priority 1 targets. For an Autumn launch (Sagittarius-hole observable), 19.38 hours of LWS Guaranteed (spacecraft) time will be allocated, of which 7.31 hours will be for Priority 1 targets. 3.5 hours of Mission Scientist (H.J. Habing) Guaranteed time is being used for this project, with the remainder coming from LWS Consortium Guaranteed time.