Edgar Award - winning author Domenic Stansberry is known for his intensity - his dark thrillers, thick with suspense, in which the differences between good and evil are not so easy to decipher. The Big Boom is just such a novel: set in San Francisco, at the peak of the high-tech frenzy, just before the technology markets and the California economy all go bust.   The Big Boom features the return of Dante Mancuso, the hero of Stansberry's Chasing the Dragon, an obsessive private investigator working the streets of his San Francisco neighborhood. He is a dark-eyed, complex figure - melancholic, tender, with fierce, aquiline good looks - known to neighborhood familiars by his nickname: the Pelican. Dante's nickname - like the demons that haunt his personal life - comes from his family on account of his tenacity, and his large, Sicilian nose.   Now Dante has settled into a new apartment in North Beach, hoping to put those demons behind him and patch together a life with his longtime lover, Marilyn Visconte, but before long he is approached by an old North Beach family in hopes that he will find their missing daughter - a young woman, a former sweetheart, with whom Dante had been involved years before - and his newfound peace is shattered.   Dante's search for Angela Antonelli, though, has hardly begun when the corpse of a young woman is dredged from the bay. He soldiers on in his investigation, fearful that the missing woman and the corpse are one and the same.   His search for the missing woman - even after he has been called off the case - becomes an obsession that alienates his current lover, but Dante follows the ghostly trail anyway into the heart of the financial district and the underside of the dot-com revolution. It is a quest rendered in the staccato prose of the genre, a style that - in Stansberry's hands - takes on a dreamlike cast, hallucinatory at times, blurring the lines between reality and Dante's own dark nostalgia.   The Big Boom is a tightrope of a novel, a taut story about familial duplicity, personal greed, and the desperate pull of love even across the divide of memory.