Narcissa Whitman and her husband, Marcus, went to Oregon as missionaries in 1836, accompanied by the Reverend Henry Spalding and his wife, Eliza. It was, as Narcissa wrote, "an unheard of journey for females."   Narcissa Whitman kept a diary during the long trip from New York and continued to write about her rigorous and amazing life at the Protestant mission near present-day Walla Walla, Washington. Her words convey her complex humanity and devotion to the Christian conversion and welfare of the Indians. Clifford Drury sketches in the circumstances that, for the Whitmans, resulted in tragedy.   Eliza Spalding, equally devout and also artistic, relates her experiences in a pioneering venture. Drury also includes the diary of Mary Augusta Dix Gray and a biographical sketch of Sarah Gilbert White Smith, later arrivals at the Whitman mission.