The first Born approximation provides a useful means to study scattering of ultrasound by various defects. In particular, it seems to yield qualitatively good results for the scattered power, when averaged over a range of frequencies. Features of the scattered power that have been discovered by this method will be reviewed. Closer study of some of these features leads to a step procedure to characterize an oblate spheroidal defect; to determine its orientation and shape. Procedures for extension to other shapes can also be given. Areas of future development will be indicated.