Increasing violence perpetrated by drug trafficking organisations (DTOs) and other criminal groups is threatening citizen security in Mexico. Mexican DTOs dominate the illicit drug market in the U.S. and are expanding their operations by forming partnerships with U.S. gangs. As a result, some of the drug-related violence in Mexico has spilled over into the United States. On October 22, 2007, the U.S. and Mexico announced the Merida Initiative, a proposed package of U.S. counter-drug and anticrime assistance for Mexico and Central America that would begin in 2008 and last through 2010. This book provides an overview of the funding provided for the Merida Initiative, the status of Merida implementation, and a discussion of some policy issues that Congress may consider as it oversees the Initiative.