This Sunday marks three months since the last U.S. military convoy left Iraq. Few places were better witnesses of the effects of the war on citizens than Ibn Sina Hospital in Baghdad’s Green Zone, which is perhaps most familiar to Americans for its emergency room, known as Baghdad ER. Each day, the American-run Baghdad ER treated anyone who came to its door with life-threatening battle injuries. On October 1, 2009, the U.S. government returned management of the hospital to Iraq. One of the people who witnessed all of this firsthand is Dr. Todd Baker, the chief of Baghdad ER from November 2007 through January 2009. He earned the Bronze Star Medal and Combat Action Badge for his work there, and is now the co-medical director of the emergency department at Skaggs Regional Medical Center in Branson, Mo. Dr. Baker has written about his experiences in Iraq in a new memoir, “Baghdad ER: Fifteen Minutes.”