Host-guest, guest-guest, and host-host interactions in the beta-hydroquinone clathrate crystal have been calculated from periodic and cluster-type ab initio calculations. The potential energy surfaces for the positions of the enclosed guest molecules in the cage have also been studied. The host framework remains virtually unchanged upon guest enclosure. The inclusion energy for the polar HF molecule is about -7 to -9 kcal/mol, in good agreement with our extrapolation from existing calorimetric data for HBr and HCl, and about -1 to -2 kcal/mol for Ne. The guest-guest interaction is small.