Infrared spectroscopy is the most generally applicable of all characterization tools for qualitative analysis, but it is perhaps one of the most difficult to exploit to its full potential. Recent developments in instrumentation allow spectra to be obtained under difficult conditions of low sample transmission, low concentration, spectral overlap and rapid spectral change: these developments include Fourier transform infrared spectroscopy, ratio-recording dispersive spectrometers, photovoltaic and photoconductive detectors, and computer manipulation of spectra. Simpler spectrometers with fixed or variable frequency filters are particularly suitable for commercial and industrial applications, and tunable infrared lasers are potentially powerful tools for detecting and measuring atmospheric contaminants. Recognition of spectra, even with computer searching of data banks, remains a challenge, and human pattern recognition and intelligence are still essential tools in the fields of minerals, and inorganic and biological materials. There is now an urgent need for detailed monographs on specific groups of compounds to give potential users readier access to sound correlations of spectra and structure.