''Beyond the edge of the world there's a space where emptiness and substance neatly overlap, where past and future form a continuous, endless loop. And hovering about there are signs no one has ever read, chords no one has ever heard."
That haunting passage comes close to the end of Haruki Murakami's ''Kafka on the Shore," but it might just as well have served as the preface, marking the entrance to the fabulous trail through identity, mythology, philosophy, and dreams that is this book.
Two main characters lead the journey, approaching from different directions and converging in a manner that is no less suspenseful for being inevitable. Kafka Tamura is a smart and solitary boy who has run away from home to avoid his father's prediction that, like Oedipus, he will one day kill his father and sleep with both the mother and stepsister who abandoned him when he was 4 years old. Nakata is the survivor of a mysterious event that occurs in an unnamed Japanese town in 1944, when a group of schoolchildren, out mushroom-picking with their teacher, suddenly crumple to the ground unconscious but with eyes wide open, raptly observing something not visible to the adults that tend to them. All but Nakata awake within hours, with no memory of what has occurred. But Nakata remains in this mysterious state for several weeks, and when he does return, he has forgotten everything he knows. Now, in his 70s, he is an apparent simpleton, unable to read or write but able to converse easily with cats and predict when mackerel and leeches will fall from the sky.
On his 15th birthday, Kafka takes all the money from his father's study and boards a train to Takamitsu, a seaside city far from his home in Tokyo. There he discovers and takes up residence in a small, private library where he is befriended by Oshima, a kind, erudite woman who lives life as a gay man and serves as Kafka's protector, confidante, and guide. However, Kafka is also mesmerized by the library's 50ish director, Miss Saeki, and the ghost of her as a girl of 15, both of whom engage him emotionally and sexually. Is Miss Saeki his mother? His sister? Or just an older woman trying to relive the great passion of her life, to negate the loss of the boy she loved at the age of 15 and lost at 20?
For Kafka, ''Fate is like a small sandstorm that keeps changing directions. You change direction but the sandstorm chases you. You turn again, but the storm adjusts. Over and over you play this out, like some ominous dance with death just before dawn. Why? Because this storm isn't something that blew in from far away, something that has nothing to do with you. This storm is you. Something inside of you. So all you can do is give in to it, step right inside the storm, closing your eyes and plugging up your ears so the sand doesn't get in, and walk through it, step by step." This remarkable protagonist, ''the toughest 15-year-old on the planet," alternately tries to escape and embrace the fate that his father has prophesied for him, discovering along the way that ''It's not so easy to make choices on your own." Indeed, in some respects this book is a primer on existentialism, but in Murakami's capable hands, weighty philosophical matters are unpretentiously filtered down to a simple, poignant question posed by a boy who was abandoned by his mother, a man-child without moorings, who wonders, ''All I know is that I'm totally alone . . . Is this what it means to be free?"
Meanwhile, Nakata is feeling his way toward realizing his destiny, which is entwined with those of Kafka and Miss Saeki. He is aided by some of the most accessible and sympathetic characters that Murakami has ever created -- several cats; an easygoing, unambitious truck driver named Hoshino; and Hoshino's guardian angel, a ''metaphysical, conceptual object" who takes on the physical form of Colonel Sanders and spouts philosophy and theology while pimping in the back alleys of Takamatsu.
As in most of Murakami's books, Japan's wartime history provides a kind of white noise. But in this novel, the struggle to break free of a legacy of conformity and militarism is much more explicit. Two ageless Japanese military deserters serve as Kafka's guides at a key moment, and all of the characters are without families, elders, or affiliations. They are isolated, lacking any identity except that which they are gingerly, tenderly creating for themselves and in relation to one another.
As in ''The Wind-Up Bird Chronicle" and ''Dance Dance Dance," Murakami creates a magical reality in which past and present, dreams and reality merge like the sides of a Mbius strip. But in this book he expands his reach, dipping into Greek mythology, personal and national identity, Christianity, and literary criticism -- doing it all without flamboyance and in service to the story.
''It's all a question of imagination," scribbles the librarian Oshima in the back of a book about Adolph Eichmann. ''Our responsibility begins with the power to imagine. It's just like Yeats said: 'In dreams begin responsibilities.' Flip this around and you could say that where there's no power to imagine, no responsibility can arise."
Murakami's power to imagine is breathtaking and the empathy infusing ''Kafka on the Shore" makes it a responsible book, one that is adult, wise, and forgiving.