The Other Place, the astral plane, the land of dreams-it's not a real place like, say, Walsall. But it's a metaphor for a mathematical abstraction, a manifold containing an n-dimensional space where everything is the product of geometrical transformations, including mass and energy and time. Leakage between dimensions occurs there: it's how we summon demons from the vasty deep, communicate with aliens, and try to extract our tax codes from the Inland Revenue.