On September 11, 2001, 2,792 people were killed in terrorist attacks on the World Trade Center (WTC) in New York City. The number of victims, the condition of their remains, and the duration of the recovery effort made the identification of the victims the most difficult ever undertaken by the forensic community in this country. In response to this need, the National Institute of Justice (NIJ), the research, development, and evaluation agency of the U.S. Department of Justice, brought together a group of experts to provide advice and support throughout the identification effort. Called the Kinship and Data Analysis Panel (KADAP), the group made recommendations on new forensic technologies, tools, policies, and procedures to help identify those who perished in the WTC attack. This report contains the KADAP's "lessons learned," particularly regarding DNA protocols, laboratory techniques, and statistical approaches, in the DNA identification of WTC victims.