Conventional crystal structure analysis using Bragg diffraction data reveals only average one-body structural information, such as atomic positions, thermal ellipsoids and site occupancies. Diffuse scattering, on the other hand, gives two-body information and is thus potentially a rich source of information of how molecules interact. However, since typical diffuse scattering intensities are ∼lO3-lO4down on Bragg intensities, obtaining such information is still a far from routine process and quantitative studies are rare. In this paper we describe some of the concepts and difficulties involved, with particular reference to the example of 1,3-dibromo-2,5-diethyl-4,6-dimethyl benzene (BEMB2), which is disordered as a result of the fact that the molecule can take up either one of two different orientations in a given molecular site.