The huge improvement in sensitivity provided by the Infrared Space Observatory (ISO) offered the opportunity to probe the galaxy population to higher redshift than the Infrared Astronomical Satellite (IRAS) and to make progress in understanding the obscured star-formation history (SFH) of the Universe. The ``European Large Area ISO Survey'' (ELAIS) represents the largest non- serendipitous survey conducted with ISO (Oliver et al. 99, MNRAS submitted). This survey provides a link between the IRAS survey, the deeper ISO surveys and the sub-mm surveys. The main goal of this proposal is to study the history of star formation and cosmic evolution of galaxies determined from mid- and far- IR, radio, and U-band tracers, which not only determines the history of metal production but is of fundamental importance to our understanding of galaxy formation and evolution. ISO mid-IR surveys in the CFRS and HDF yield estimates of the SFR 3-6 times higher than those from optical/UV surveys, casting doubt on the usefulness of the latter. Deep radio surveys of the HDF confirm the ISO star formation rates (SFR). We request 4 nights of WIYN/HYDRA to undertake a spectroscopic survey of ~ 1000 R< 20 galaxies associated with sources detected as part of the ELAIS survey at 21cm, 90, 15, and 7(micron) and in the U-band, to provide the definitive estimate of the local (z< 0.6) SFR, resolving the issues of dust obscuration affecting these estimates.