marine infantry officer david morris sits down with iraq war veteran and a rand corporation's kayla williams. the two talk about the history of post-traumatic stress disorder and the 27 million americans including david morris himself who currently suffer from ptsd. ms. williams is also the author of plenty of time when we get home, love and recovery in the aftermath of war. >> host: i am kayla williams. i'm a combat veteran of the iraq war and the spouse of a wounded veteran. my second book chronicles my family's journey after my husband sustained a traumatic brain injury in iraq and develop post-traumatic stress disorder. so it is both with personal and professional interest that i'm tremendously pleased to sit down today with david morris and have a conversation about his new book "the evil hours" a biography of post-traumatic stress disorder. thanks so much for joining me today. >> guest: thanks for having me. >> host: i wonder if he could start about the telling me about yourself and why he wanted to write this book. >> guest: it's difficult to answer. in some ways i had always lived in