This week, Martha sits down with author Toby Harnden, to discuss his new book First Casualty: The Untold Story of the CIA Mission to Avenge 9/11, and why he decided to revisit the story of the first CIA military group to get into Afghanistan.

Toby shares he wrote this book for people to understand where America has been in order to remember how this war began and to bring that knowledge to where America is now as we try to navigate the relationship with Afghanistan.

Follow Martha on Twitter: @MarthaMacCallum