Pat Tillman's Final Love Letter: NFL Star's Wife Shares Message

A love letter from Pat Tillman, who left a promising career with the NFL to join the army, has been revealed by his wife Marie in a new book.

Tillman enlisted in the U.S. Army in June 2002 following the 9/11 terrorist attacks the year before.

The football player left his wife a letter to open in the event of his death, which was left unopened after two deployments. Then, during Tillman's tour in Afghanistan, he was killed at age 27 by friendly fire in 2004. It was then that she opened the final letter.

Together since high school, Marie Tillman penned a book about her 11-year relationship with the football star and war hero, titled "The Letter: My Journey Through Love, Loss, & Life," in stores Tuesday.

It is in the book that Tillman's last letter is highlighted.

"It's difficult to summarize 10 years together, my love for you, my hopes for your future, and pretend to be dead all at the same time," Tillman's words read, as written in the new book "The Letter."

"I simply cannot put all this into words," Tillman wrote. "I'm not ready, willing or able."

Tillman was inspired to write the book by the hundreds of letters she and her husband exchanged over the course of their relationship, and especially the last note.

Although she keeps most of her late husband's final letter private, she does reveal a paragraph where he urged his wife to move on with her life in the event of his death.

"Through the years I have asked a great deal of you," wrote Tillman. "Therefore it should surprise you little that I have another favor to ask. I ask that you live."

Now 35 years old, Marie has since remarried and shares one son with Joe Shenton, a divorced father of three. She lives in Chicago and continues to work for veterans through the Pat Tillman Foundation.