Mormon Enigma: Emma Hale Smith, Linda King Newell and Valeen Tippetts Avery.
After more than a year of research into all things Mormon the above book is the one that sealed the deal for me in relation to leaving the church.
No Man Knows My History: the life of Joseph Smith, Fawn M. Brodie.
I read Brodie's book after I was clear of the religion. It was an enthralling read. However it looks as though Mormon apologists have some concerns over some of her sources so I will be more cautious when I reference her in the future. There is plenty in Mormon Enigma and other books anyway so I still have many things that I want to post here. I feel I owe it to Emma somehow.