As she lies dying of cancer in ""El Bronx,"" 40-year-old Puerto Rican woman Isabel Encarnacion recalls her grim, sad, short life--beginning with her mother's long-ago flight to New York. At first Isabel concentrates on one brief joyful time: her visit, at 20, to her long-unseen father in Puerto Rico--finding him an old but handsome fisherman, meeting her young half-brother, rediscovering the island's beauty. But she must also remember how the visit ended--in ugliness, when her father made it subtly clear that he didn't believe Isabel's lies about life in N.Y., that he knew that she was working as a prostitute (not at ""the school for secretaries""). And then, as the narrative becomes more straightforwardly chronological, Isabel sets out the plain, painful facts of her life in Manhattan: teenager years, darkly shadowed by her mother's murder of Isabel's prostitute-sister (ever since, mother Clara has been locked up in an asylum for the criminally insane); Isabel's dreary 1950s days as a prostitute, with dangerous Harlem abortions; her total devotion to short, handsome, half-Jewish cat burglar Marlo, a.k.a. ""Electrico,"" helping him with a couple of daring heists (and getting brutally beaten up in the process), their shaved drug addiction; her always-thwarted dreams of a better, cleaner life in El Bronx--which do seem to come true after Mario nearly dies of an overdose, is crippled by a stroke, and agrees to go straight. (""I had fallen into the flames and been burned and could not ever ride the black racing motorcycle again."") But Isabel's El Bronx happiness--a small beauty-salon, baby Victorcito, law-abiding husband Marlo--lasts only a very little while: the final 100 pages here relentlessly follow the nightmare of Isabel's breast cancer--from first anxieties to terrifying city-hospital procedures (Isabel has sex with an intern to gain a ""friend"" in this fearsome place), from traumatizing surgery to Isabel's decision to seek spiritual peace and refuse any further treatment: ""I did not want for them to cut me up and cut me up until there was nothing left of me but crab's claws and shark bites."" First-novelist Preston sometimes piles on the stark pathos here a bit too heavily--as when Isabel discovers her long-lost mother in the same hospital ward, dying horribly (with a merciful assist from Isabel). There's little texture in the serviceable, Spanish-dotted narration, little shape in the drama; the final attempt at uplift is unconvincing. But, with enough unhackneyed details to provide a measure of harsh authenticity, this woeful chronicle has some of the flat, raw, documentary power of a social worker's most dreadful case histories.