In recent years a general theory has been developed for inverting Fourier transforms on non-unimodular locally compact groups. The few known explicit examples have been solvable or have fit into the framework: parabolic subgroup of semisimple Lie group, in which the nilradical has square integrable representations. That class of parabolic subgroups is interesting in its own right; it occurs in many geometric situations, and it has a large overlap with the class of maximal parabolic subgroups.