Plural Marriage in Kirtland and Nauvoo

Here is a link to a lengthy list of helpful quotes on this topic.
I can't say enough good about the work of Brian Hales on this subject. His work Joseph Smith's Polygamy, (volume one/volume 2/volume 3) is a nearly comprehensive covering of plural marriage in the early church. If, however, you are not up for 1,500 pages of reading on a single topic, he has created a highly condensed version titled Joseph Smith's Polygamy - Toward a Better Understanding, that briefly covers each aspect of the subject. For most, this abbreviated version covers the topics sufficiently (and is far less expensive).
I also enjoyed Laurel Thatcher Ulrich's A House full of Females. She is a renowned, Pulitzer Prize winning author, and does a great job making the history come alive withe stories.
Lastly, Richard Bushman adds a fair amount of insight into plural marriage in his biography of Joseph Smith, Rough Stone Rolling.