 Aharonov and Bohm (1959) drew attention to the quantum mechanical prediction that an interference pattern due to a beam of charged particles could be produced or altered by the presence of a constant magnetic field in a region from which the particles were excluded. This effect has since been experimentally demonstrated. At first sight, the Aharonov-Bohm effect seems to involve action at a distance. It seems clear that the (electro-)magnetic field acts on the particles since it affects the interference pattern they produce; and this must be action at a distance since the particles pass through a region from which that field is absent. But alternative accounts of the phenomenon are possible which portray it rather as a manifestation of (strong)  nonseparability  (Healey 1997). There need be no action at a distance if the behavior both of the charged particles and of electromagnetism are nonseparable processes. While such a treatment of electromagnetism (and other gauge theories) is increasingly common in physics, to treat the motion of the charged particles as a nonseparable process is to endorse a particular position on how quantum mechanics is to be interpreted.