This series of talks is intended to give an
appreciation of a construction applicable to a very wide range
of physically interesting spacetimes. Emphasis will be more
on presentation of the issues involved (chiefly causal
structure and topology), than on intricacy of detail, with the
aim being to show how the causal boundary allows one to view a
spacetime "from infinity", with a concrete picture of just
what that infinity looks like. We'll start with an
introduction to what a spacetime is, from both mathematical
and physical considerations. A very basic notion of
(pseudo-)Riemannian manifolds will be helpful, but the ideas
should be clear even without that knowledge.