"On January 24, 2003, the Department of Homeland Security (DHS) began operations. The creation of the department, representing the largest reorganization in Federal history since the creation of the Department of Defense in 1947, brings together 22 different Federal agencies and approximately 180,000 employees. The mission of the department (preventing terrorist attacks within the United States, reducing the vulnerability of the United States to terrorism, minimizing the death and destruction resulting from terrorist attacks, and assisting with the recovery from any such attack) is of paramount national importance. DHS is organized into five divisions or 'directorates.' The largest of the directorates, Border and Transportation Security, is responsible for maintaining the security of our nation's borders and transportation systems. It brings together the functions of the U.S. Customs Service, the Transportation Security Administration (TSA), and the border security functions of the Immigration and Naturalization Service (INS). The Emergency Preparedness and Response directorate works to ensure that our nation is prepared for and able to recover from terrorist attacks and natural disasters. It assumes the work and role of the Federal Emergency Management Agency (FEMA), and it absorbs the functions of the Office of Domestic Preparedness in the Department of Justice (Justice). The Science and Technology directorate houses the department's research and development activities, which are designed to find ways and means to thwart terrorist attacks and to minimize their effects."