While this will be an emotionally difficult read for me, I'm nominating:
Ted Hughes, Birthday Letters
This is a book of poems addressed to Sylvia Plath, his wife, who suffered from depression and later committed suicide. There's some controversy about this book as some people have intimated that Ted was involved in or responsible for Sylvia's death.
Here's what Yann Martel tells Stephen Harper about why he sent him this book:
What Stephen Harper is Reading, Birthday Letters