I'll never understand that library

Why do they have The Dragon and the George filed under general fiction while every other book they have from Gordon, R. Dickinson is filed under science fiction/fantasy? Sure, the line between the two categories is arbitrary, but I think it's fairly obvious where this particular book falls. Considering the astral projection machine that starts the whole mess, there might be some argument as to whether it's fantasy or sci fi, but if being sent to inhabit the body of a dragon in another world isn't one or the other I would like to know why I wasn't told!