The separation of signal and noise is a central issue in seismic data proce
ssing. The noise is both random and coherent in nature, the coherent part o
ften masquerading as signal. In this tutorial, we present some approaches t
o signal isolation, in which stacking is a central concept. Our methodology
is to transform the data to a domain where noise and signal are separable,
a goal that we attain by means of inversion. We illustrate our ideas with
some of our favorite transformations: wavelets, eigenvectors, and Radon tra
nsforms. We end with the notion of risk, baseball, and the Stein estimator.