Antonio Tabucchi (1943-2012) was one of the leading writers of comtemporary Italian literature particularly with his profound and disquieting novels and essays. Through both types of novel and essay, he settled effectively his own way of questioning how we exist and at the same time how we should cope with social and political problems. It is controversial whether his writings can be classified into the field of postmodern literature, but this issue seems to be less crucial than shedding light on the unique consciousness and technique of in his writings. This article aims to show through close reading of Il filo dell`orizzonte (1986) that we need to consider Tabucchi`s literature from more fundamental and conflicting dimensions of metaphysics and ethical practice. In Il filo dell`orizzonte Tabucchi describes the complex structures of an individual`s inside (or unconsciousness) and its relationship with sociohistorical conditions. The protagonist Spino strives to identify the unknown man (his name is Carlo Nobodi) by meeting diverse people who are situated in a peripheral area of human society and by developing a negative film of Nobodi. It is ironic that for Spino the process of tracing the identity of Nobodi is not different from reconstituting his own identity; in the whole process he recalls his past (through the experience of watching the old films) and speculates about the possible structures of the things and time, and finally discovers that his identity is inexorably connected with all other people and things in the world. Now he finds himself standing on the borderline between presence and absence, life and death, yet he feels most happy and comfortable since he has explored the unsolved area of human and social worlds. In the beginning of the novel Spino was immersed in the old films whereas in the end he learns a sense of liberty through dream which is a cure of his existence rather than a promise of the future. As Tabucchi reminds us in his Author`s Note, it is impossible to reach the edge of the horizon since it always recedes before us, but he suggests that we, like the philosopher Spinosa (and his namesake Spino), bear already the edge itself in our eyes; this is also what Spino seems to conclude at the end of his pilgrim in the question of existence.