Wave propagation is an exciting ?eld having applications cutting across many disciplines. In the ?eld of structural engineering and smart structures, wave propagation based tools have found increasing applications especially in the areaofstructuralhealthmonitoringandactivecontrolofvibrationsandnoise. Inaddition,therehasbeentremendousprogressintheareaofmaterialscience, wherein a new class of structural materials is designed to meet the parti- lar application. In most cases, these materials are not isotropic as in metallic structures. They are either anisotropic (as in the case of laminated composite structures) or inhomogeneous (as in the case of functionally graded mate- als). Analysis of these structures is many orders more complex than that of isotropic structures. For many scientists/engineers, a clear di?erence between structural dynamics and wave propagation is not evident. Traditionally, a structural designer will not be interested in the behavior of structures beyond certain frequencies, which are essentially at the lower end of the frequency scale. For such situations, available general purpose ?nite element code will satisfy the designer's requirement. However, currently, structures are required tobedesignedtosustainverycomplexandharshloadingenvironments. These loadings are essentially multi-modal phenomena and their analysis falls under the domain of wave propagation rather than structural dynamics. Evaluation of the structural integrity of anisotropic and inhomogeneous structures s- jected to such loadings is a complex process. The currently available analysis tools are highly inadequate to handle the modeling of these structures. In this book, we present a technique called the "Spectral Finite Element Method",whichwebelievewilladdresssomeoftheshortcomingsoftheexistinganalysis tools.