  Roche tomography is a technique designed for mapping the intensity
distribution over the surface of binary star components that fill (or nearly
fill) their Roche lobes and so are both rotationally and tidally distorted. It
builds on and develops the successful techniques used for mapping rapidly
rotating single stars, which have revealed the presence of starspots. It has so
far been applied to only a small number of cataclysmic variables, and a few
other related systems. This paper reviews the technique and presents maps of
spots on most of these systems. The review has been written with the help of
contributions of material from Chris Watson and Colin Hill of Queen's
University, Belfast.
