In Paulo Coelho's novel, The Alchemist, foreboding appears with regard to the caravan in which the boy travels.
First, Dictionary.com defines "foreboding" as:
1. a prediction; portent. 2. a strong inner feeling or notion of a future misfortune, evil, etc.;
Before the boy and the Englishman even leave with the caravan, the tone of danger is created with the following:
I'm the leader of the caravan," said a dark-eyed, bearded man. I hold the power of life and death for every person I take with me. The desert is a capricious lady, and sometimes she drives men crazy.
Right away, the sense of one's tenuous grasp on life in the desert is presented, along with the fact that this man has control over life and death.
The leader also admonishes the group:
...swear by the God you believe in that you will follow my orders no matter what. In the desert, disobedience means death.
These two passages present the reader with the sense that the desert is a dangerous, unpredictable place. One evening a camel driver comes to sit with the Englishman and the boy, and warns:
There are rumors of tribal wars...Once you get into the desert, there's no going back..you have to worry only about the best way of moving forward.
The hooded Bedouins reappeared more and more frequently, and the camel driver—who had become a good friend of the boy's—explained that the war between the tribes had already begun. The caravan would be very lucky to reach the oasis.
These two passages warn of the dangers of tribal wars; the second passage again refers to the mysterious Bedouins who quietly travel and provide "warnings about thieves and barbarian tribes." Their presence indicates a real danger moving throughout the desert.
When the boy sees the hawks flying over the oasis, and one attacks the other, this, too, brings a sense of foreboding, and also a premonition that the oasis is going to be attacked.
All of these examples of foreboding culminate in the attack of the oasis by an army, even though the oasis is supposed to be a neutral territory.
The idea of looking for examples of foreboding during the journey with the caravan is very similar to the boy's search for meaning in all things he witnesses, even while he travels with the caravan.