Dreams are mysterious.
Once I came across a book, 'Mysterious thoughts and Occult arts' describing exploitation of six inner senses among which besides clairvoyance, telepathy etc.,there was description of events when dreams have come true and helped to avoid many accidents.Mostly one dreams what one is engrossed with during the day as It is said that a dog dreams crushing bones in his mouth.But at times one finds himself viewing the past events or future happenings too. Some can interpret the dreams which often come true.
Dreams have helped in the discoveries too like the formula for glucose when the scientist dreamed a snake forming a ring and he got the idea of hexagon.