One of the four grants addressed the "Dynamics of Retail Methamphetamine Markets in New York City." This study used Internet recruitment and respondent-driven sampling in interviewing 132 methamphetamine users, buyers, and sellers in New York City in a social network analysis. The second study summarized examined "The Dynamics of Methamphetamine Markets: A Systematic Approach to the Process." This research was based on a survey of 1,367 law enforcement agencies, along with WebEx/telephone interviews, using interactive maps with narcotics police in 50 jurisdictions. The third project summarized addressed "Drug Market Characteristics: Antecedents and Sequelae on the U.S.-Mexico Border." This study focused on retail drug markets in relation to drug-use patterns, medical consequences of drug use, and cross-border mobility among injection drug users on the western U.S.-Mexico border. The sample was drawn from ongoing studies on both sides of the border. The fourth study summarized involved "Assessing the Development of Drug Markets Using Bayesian Space-Time Models." In this study, Bayesian space-time disease models of hospital discharge data from 1995-2007 across ZIP codes in California indicated that rates of methamphetamine use were greatest among White and Hispanic low-income populations living in suburban and urban peripheral areas of the state.