If you're in the right place at the right time, it's surprisingly easy to see what's coming and can make somewhat informed investments. In 1990 I worked in a lab that supplied an item used to manufacture military weaponry, that normally was purchased one drum at a time. Six weeks before Desert Storm started, we began getting multiple orders for ten drums at a time, and a letter that we were a priority manufacturer that must be given any raw materials from suppliers that we would need to fulfill the orders on time. We figured that Iraq was going to get pummeled no matter what. Anyone that bought stock in war time suppliers, at that time did alright. On the other hand, when orders slowed down, or were pushed back, we knew things were about to change in the other direction.