This paper is a descriptive statement of a talk presented to the Wood Artifacts Group at the American Institute for Conservation meeting in 1987. It describes how Fourier-Transform Infrared spectrometry (FTIR) operates, how FTRI differs from dispersive IR, and what the advantages and disadvantages of each type of analytical instrument are. Also included are some examples of how FTIR is used to identify various materials of intrest to furniture conservators.