Click for Part 1. Here I'll cover the second half of the book, roughly 1844-79. After Joseph died, life got progressively uglier in Nauvoo (after a brief respite). For Emma it was even worse--not only had she lost a husband, but her financial affairs were inextricably intertwined with Joseph's estate and with the Church. A real mess, especially since Brigham Young seemed to take the approach that most of Joseph's assets should pass to the Church but all his debts should pass to Emma. Her relations with the emerging leadership (Brigham Young and Heber Kimball) were also complicated by the fact that Emma did not want to become an odd sort of polygamous trophy wife to one of the Brethren, the fate of most of Joseph's "other wives."
In the end, she just stuck it out in Nauvoo (she got the Nauvoo House), monogamously married a fairly decent man who treated her and the kids rather well, finished raising her kids to adulthood, then died in Nauvoo on April 30, 1879. She was extraordinarily kind and compassionate, as shown by more than a few events in the book. It's worth your time to read it. I'll just dash off a few summary comments on the sons and daughters of Joseph Smith, neglected subjects of standard LDS histories.
Julia , the surviving Murdock twin, ran the Nauvoo House with her husband for awhile, but he died as a result of burns from a steamship boiler explosion in 1853. She later remarried an alcoholic, which didn't turn out well--he later headed off to New Mexico, "a vagabond" (p. 300). Julia died of cancer in 1880 (p. 306).
Joseph III eventually succeeded to leadership of the Reorganized Church and became a lifelong opponent of both polygamy and also of the idea that his father had anything to do with it. He was encouraged in this by his refusal to quiz his mother on what really went on, then by her utterly misleading statements when he finally did interview her (p. 300-02). Just another twist in the whole messy polygamy story. A good deal of the documentation we do have comes from Utah Mormons who produced lots of personal accounts of polygamy under Joseph in Nauvoo to counter Joseph III's charges that it was all Brigham's idea. He named his first daughter Emma. He died in 1915.
Frederick married in 1857 but the marriage failed. His health was poor and he died in 1862 at age 26 in Navuoo (p. 274-75).
Alexander served faithfully as Patriarch, Apostle, then Counselor to his brother Joseph III in the RLDS Church until his death at Nauvoo in 1909 (p. 308).
David, the youngest son, was first struck by an episode of mental illness while on a mission for the RLDS Church in Utah in 1872 (p. 289). It came and went but intensified over time; in 1877 he entered the Illinois State asylum where he remained until his death in 1904 at the age of 59 (p. 306).
Note: All About Mormons posts the short Encyclopedia of Mormonism biography of Emma Smith.