ONCE AGAIN Scott Spencer's subject is obsessive love. In Endless Love, his previous novel, it was the love of a teenaged boy for his girlfriend, a passion precocious in its sexuality and, in the end, cruelly destructive. In Waking the Dead it is the love of a man in his mid-thirties for the woman with whom he lived for several years; she was killed in an automobile accident five years before, but he cannot get her out of his mind and finally comes to believe that she is in fact alive. The difference between the two books is that Waking the Dead is about a great deal more than love; the story of Fielding Pierce and his unshakable devotion to Sarah Williams is also about politics, class, family, destiny and moral choice.

It is an ambitious novel and on the whole an admirable one. Though it does not have the sheer emotional force of Endless Love -- one of those rare works of fiction that almost literally sweeps the reader away -- it is energetic and intelligent. Its cast of characters is as broad and various as its thematic material, and each member is made exceptionally vivid; even the walk-ons, such as the political gofers and hangers-on who attach themselves to Pierce's campaign for Congress, are distinctly individual and believable. The novel is narrated by Pierce and is least successful when he takes an introspective turn; its best passages, of which fortunately there are many, are those in which dialogue dominates. As a portrait of contemporary urban life, Waking the Dead is mordant, unsentimental and frequently amusing.

Fielding Pierce is one of three children of working-class parents from Brooklyn; his father is about to retire as a printer at The New York Times, and his mother is a secretary for a small-time politico. The parents are proud of themselves and their class, yet determined that their children shall rise above it. From boyhood Fielding -- the name itself suggests the lofty aspirations his parents have for him -- has been, as Sarah puts it, "the incarnation of your family's ambitions," and he is determined to fulfill them. He is that distinctly American phenomenon, the "self-invented" person who sees himself as "a two-destiny guy, the one being the life I'd been born to and the other being the life I desired."

Sarah is the embodiment of the latter. She is smart and beautiful, but passionately unconventional; she has a "look of absolute vulnerability laced with a love of adventure," qualities ill-suited to the life of conventional three-piece-suit success to which Fielding is committed. Yet when he meets her in New York -- it is the early 1970s and he is in the Coast Guard, en route from Harvard to the University of Chicago Law School -- he falls hopelessly in love with her, and she with him. She is an idealist and he a pragmatist, but "I still believed Sarah and I were united in a belief in the same sorts of things and separated only by matters of temperament and taste."

When Fielding moves to Chicago to begin law school Sarah joins him, but soon she makes a commitment that ultimately proves fatal in more than one sense. She joins the staff of Resurrection House, run by radical Catholic priests and nuns as "a place where the homeless, the afraid, where all souls on the loose might gather." It becomes a haven for refugees from the post-Allende military government in Chile; before long Sarah is involved in illegal activities on their behalf. She goes to Minneapolis on one such mission "with our life together in the worst possible repair" because her involvement with Resurrection House has drawn her away from Fielding. He learns from a report on national television that she and two refugees have been killed in a bombed automobile.

HE IS DEVASTATED, yet even at Sarah's funeral he understands that "this loss would forever embrace my life but it would not stop it," that "I had already begun to adjust to life without her." He returns to law school, and after graduation begins a career under the tutelage of Isaac Green, a sophisticated, cynical older man who sees in this "hungry, cold, self-serving little nobody from nowhere" the means to fulfillment of the aspirations that his own son has rejected. Green has great influence with the governor of Illinois, so when the congressional seat in the district where Pierce lives suddenly becomes vacant, he proposes that the governor support his protege in the special election. He tells Pierce:

"We come from a long tradition, Fielding. And what's at stake here is nothing less than civilized values. This is an age of mediocrity. Synthetic suits and those enormous portable radios. Barbarism. It's all around us, everywhere. Someone told me they make toilet paper printed up to look like the flag now. Can you imagine? Who can even count how many illegal guns there are in this city alone? Three hundred thousand, at least. This is a desperate time and a marvellous opportunity. You'll shine amongst them, Fielding. Shine. Your honesty. Your toughness. Your respect for decency and enduring values."

But running for office turns out to be something quite different. Pierce, who genuinely wants "to be good," soon discovers that his is "a crusade that had begun, as most crusades had, with the highest ideals and the best intentions but during which I had begun to forget about the fallen torches I had once wanted to retrieve, the terrible wrongs I had wanted to redress, and now the long bloody trek to Jerusalem was something generated by fuel from a deeper and a darker source: the grade-A crude of ego." Further complicating matters is that Fielding, though living reasonably contentedly with the chic, undemanding Juliet Beck, begins to believe that Sarah has "come back from the other side, or that she never died, or that there's a secret about death that's never been known and now it's coming to light."

So at the very time that Fielding is pursuing politics, the life to which he believes himself to have been born, he is obsessed with Sarah, the life he desires: not merely for reasons of love and passion but because Sarah, who chose moral commitment over love, represents those aspects of his own character that have been suppressed by "this man running for Congress, this grinning fake with a sudden clutch of underlings, this new self that seemed to survive only by eating in large bites all of the selves that had preceded it." At a moment that is anything but opportune for his political career, Fielding turns his whole heart and soul to the search for Sarah; when at last it is over, his life has been irrevocably changed.

It is a powerful story, and this description barely begins to touch the many courses it takes -- too many, perhaps, for Spencer has difficulty sustaining the novel over its not-inconsiderable length and in the middle the pace slows noticeably. He has attempted to mix the intense emotional fervor of Endless Love with elements that are rational, at times even satirical, and the combination does not always work. But that having been said, let it be emphasized that Waking the Dead is one of the most intelligent and expansive American novels of recent years. Among its many virtues is that although it is very much a novel about politics, it has no political axes to grind and acknowledges that politics can come between people in terrible ways and at worst can destroy them. It is exceptionally well written -- brilliantly so, at times -- and filled with irresistible vitality. It gives pain as well as pleasure, but that's life.