There has been a lot of discussion in the twentieth century about eschatology. Some people think it all started with Albert Schweitzer, who wrote a lot about the New Testament and started a lot of conversations that have carried on since. He was one of the first people to realise (re-realise?) that Jesus talked a lot about the Kingdom of God, so sparked a lot of discussion about what the Kingdom of God actually was (while most people now agree with Schweitzer that the kingdom of God is really important in Jesus' teaching, they tend to disagree with him about what the kingdom of God actually is).
Jurgen Schmurgen, as we shall call him, is a German (another one) Protestant theologian. He's still alive, which seems weird to me, though maybe only because recently I've mostly been reading old dead dudes. He wrote a lot about eschatology, including an article called Liberating the Future in a book called Liberating Eschatology. In it, he argues that the modern western world tends to have two visions of the future: one, that we're progressing towards a golden age where everything is wonderful, and two, that everything's getting worse and the end is surely nigh. This leads to two tendencies: the conservative, where because we think everything's getting worse, we want strong discipline in the state, the church or the family to hold back the end, and the progressive, where our vision of the future is of continual expansion of technology and ideas, without anything really changing (see, for example, Fukuyama's The End of History, which argues that capitalism is the last great idea, and we can't really go anywhere new from here).
Nihilism: it's hardly an inspiring choice, and Moltmann argues that in a world where we lack alternative visions of the future, we badly need Christian eschatology to liberate the future with the hope of something better. He offers three guidelines for "hope in action", which he says have emerged from recent ecumenical discussions:
1) The Anticipation of God's Future. This means that instead of buying in to the miserable alternatives modern thought offers us, we should let our lives be shaped by the hope of God's promised future.
2) God's preferential option for the poor. A favourite theme of liberation theology, this means that not only is God on the side of the poor, the weak, and the oppressed, but that it is among these marginal people that we really find Jesus. If the Church just cares for the poor, it becomes an accomplice of the society that oppresses them; if it just speaks out against injustice, no one listens: the Church needs to work with and speak for the poor.
3) Correspondance and contradiction in history. The Kingdom of God is and is not present and able to be made present in the world. The Kingdom of God is involved with, for example, the fight for fair prices for coffee traders; but fair prices for coffee traders aren't in themselves the Kingdom of God. Politics should be both a parable and a preparation for the Kingdom of God, which we can never fully bring to earth ourselves.