Theoretical issues related to the Laser-Interferometer Gravitational-Wave Observatory (LIGO), most especially studies of astrophysical sources of gravitational waves, the characteristics of the waves they emit, and the implications of those characteristics for (i) the design of LIGO, (ii) the design of detectors to operate in LIGO, and (iii) the design of LIGO's data analysis methods will be investigated. Although all the research is theoretical, the project entails close interaction with gravity-wave experimenters.