Here at eNotes we can’t provide you with fully written essays, but I can give you some ideas about what you could write in your work.
First of all, you might want to elaborate a bit further on how Paul Coelho, the author of The Alchemist, presents the Greek myth of Narcissus in the prologue. Narcissus, according to the legend, was so “fascinated by himself that, one morning, he fell into the lake and drowned.” Coelho’s version, however, continues beyond this point. The author writes about how the lake was weeping after Narcissus’ death. Surprisingly, the lake wasn’t weeping because he was sad about the loss of Narcissus, but it turns out that the lake was merely mourning the fact that he could no longer admire his own beauty in Narcissus’ eyes. Therefore, you could argue that both Narcissus and the lake were obsessed with beauty. As a result, both failed to realize that there is a deeper meaning to life: the quest for one’s personal legend.
One of the reasons why this story could be interpreted as a foreshadowing of Santiago’s journey is the fact that Santiago himself is about to embark on an inner journey of change. You could easily link this development to the story of Narcissus: Unlike Narcissus, Santiago learns that there is more to life than just what appears to the eye. Focusing on just visible aspects of life, like beauty, is not sufficient if one is to pursue true happiness and fulfillment. In the course of the novel, Santiago realizes that it is not just beauty that counts. He learns to see beyond mere visual beauty in order to fulfill his own personal legend. For example, we can see this change within Santiago when we read that Santiago “was at home with the silence of the desert, and he was content just to look at the trees.”
You could also point out that the prologue contains a reference to Santiago’s physical journey. The alchemist reads the story of Narcissus in a book, which he found in a caravan: he “picked up a book that someone in the caravan had brought.” The caravan could be seen as a metaphor for traveling and therefore as a foreshadowing of Santiago’s travels ahead.