This module, adapted for the Web from the CD-ROM released in 1998, reviews GOES sounder characteristics, data products, and applications concurrent with the GOES I(8)-P satellites. Topics covered include the electromagnetic spectrum and sounder channel selection, weighting functions for temperature and moisture determination, and assessment of GOES sounder products. Sample imagery and products are provided along with several short case examples that demonstrate how these products are beneficial to meteorological analysis and forecasting applications.