Simply, the study of last things. Now, it gets tricky when one starts to apply that to the Bible. In the Old Testament, we have a number of texts that talk about what will happen in the latter days, or in the end of days — we have synonymous expressions — and typically that involves the conquering, the Messiah coming and conquering the pagan nations, the conversion of the nations, joining Israel, peace going out. Preceding that, immediately preceding that restoration in the latter days, there will be an antagonist. Daniel talks about this man of lawlessness who will come. He will spread false teaching. He will deceive Israel and deceive the nations. And so all of that will happen in the latter days. Now, the New Testament makes this remarkable insight that the latter days have begun. It's the last hour. There has been resurrection. And when we move to the book of Revelation, we see this all over the place. In fact, in chapter 1, John claims to be a partaker of the tribulation in the kingdom. So both, at the end-time tribulation and the end-time kingdom, he is participating in. And so we see that throughout the book of Revelation, not only does it concern about the very last things before the new heavens and new earth, it also concerns things that have begun from the first century to today. It has all been set in motion.