What is Eschatology?

"Eschatology is 'the doctrine of the last things.' It deals with the teaching or belief, that the world-movement, religiously considered, tends towards a definite final goal, beyond which a new order of affairs will be established, frequently with the further implication, that this new order of affairs will not be subject to any further change, but will partake of the static character of the eternal." - Geerhardus Vos in The Pauline Eschatology