The Bible is most certainly a book that contains a good deal of prophetic material, most of it in the Old Testament. It will be worthwhile then to ask, Who are prophets, and what do they do?
Prophecy is not educated guessing about the future, but rather involves the reception of a message from God about some future matter. Prophecy may come in an auditory or a visual form. If the latter, then often the prophet is called a seer or a visionary. The prophetic experience may involve some kind of ecstatic, or out-of-body, experience, but this is not necessarily the case. Sometimes, revelations come when the prophet is in a perfectly normal state of mind, and sometimes they may even come while he is asleep, in dreams.
Normally, prophetic expression involves transmitting verbatim the word of God. Thus in the Old Testament, prophecy is normally prefaced by "Thus says Yahweh," and then the utterance in question is quoted. When, however, the prophet sees a vision, he must describe it himself, and this leaves room for the use of metaphor, analogy, simile, and the like. Consider, for example, the description Ezekiel gives in Ezekiel 1 of his throne-chariot vision. He keeps groping for terms grand enough to describe the occurrence, saying over and over again, "It was like...it was like..."
Besides prophetic expression, there is also the matter of the prophetic tradition. Elijah appears to have had disciples, as did Jesus, and often the words of the prophet were passed down orally long before they were recorded. One must remember that all these ancient cultures were oral cultures, in which only 1-2% of the population was literate.
When prophecy was finally written down, there arose a prophetic body of literature, and while we may speak of the prophetic books "of" Isaiah or Amos, often it was not the prophet himself who wrote the material down. Sometimes, a prophet like Jeremiah would have a trusty scribe such as Baruch, but sometimes the prophetic material was written down only long after the prophet died.
Once the material became literature, it became possible for it to be useful to audiences beyond the prophet's original audience. It is important to bear in mind, however, that most prophecy, even futuristic prophecy in the Bible, is addressed to the audience that existed during the lifetime of the prophet himself. It was not primarily intended for Western people at the beginning of the 21st century. Nor does the meaning of the prophecy change from the time it was given until now, though its significance or application may certainly change through time. In my next column, I will talk about the subjects and substance of biblical prophecy.