Born in Transylvania at the turn of the century, Bella Cohen Spewack arrived on the streets of New York's Lower East Side when she was three. At 22, while working as a reporter with her husband in Europe, she wrote this memoir of her early years, which she never chose to publish. The publication of Streets more than 70 years later recovers a remarkable voice and revivifies a lost world.   With a sense of the telling anecdote, the young Bella describes the sights and sounds of her neighborhood, and introduces a wide array of people as her family moves annually to save rent or find a still cheaper apartment. Her mother works as a live-in domestic, then takes on sewing and eventually boarders, as well as a new and unfriendly husband. Bella's world also includes two younger brothers, one of whom needs constant nursing.   Streets includes the story of Bella's high school years-her mother was determined to make "a lady" of her daughter and would not allow her to work in a factory-and ends before she meets and marries Sam Spewack. At once street-smart and unsentimental Bella is a sturdy American hero who overcomes life's obstacles in a world that will later welcome her as a celebrated author.