The fact that wave propagation looks the same whether time is going forward or backward has been know theoretically since the formulation of wave theory. Only recently, however, has array technology and computers been developed to the point that time reversal of waves can actually be performed in real systems. Experiments using ultrasonic and underwater acoustical arrays have shown enhanced focusing, communications, and imaging through complicated media. Better theoretical understanding of the time reversal symmetry for acoustic and electromagnetic waves has motivated new techniques for imaging and characterization of targets applicable to more conventional array technology. In this talk, these new techniques for target characterization and imaging will be discussed along with examples using both experimental and computational data. It is shown that the time reversal properties of an array system can be predicted by performing a singular value decomposition of the multistatic data matrix. The spectrum of singular values and the form of the singular vectors are related to the physical properties of the target in the field of view of the array. This relationship is described for a number of simple cases and imaging techniques that exploit their properties are shown.