Modern FTIR software programs contain powerful algorithms for processing spectra. If used properly, these algorithms can enhance the information content of a spectrum, speed mixture analysis, and make spectral interpretation easier. However, if used improperly these algorithms can alter and destroy spectroscopic data and can lead to erroneous conclusions. Hence the need for this chapter. The goal here is to explain how these processing algorithms work and how to use them properly to maximize the information obtained without sacri€cing spectral quality.