Environmental criminology explores how the social, physical, psychological, and legal components of complex surroundings interact to create or facilitate the sites and situations of criminal events. Crime analysis, when linked to environmental criminology, looks at developing methods and tools for use in analyzing crimes and crime patterns. Agent-based simulation is a technique that identifies the types of individuals being modeled and specifies rules for how these individuals make decisions, how they remember past actions, and how they adapt their responses in future decisions. In an agent-based model, micro-simulations of the activities of multiple individuals are run and rerun through multiple iterations while retaining a record of and reacting to the aggregate patterns that emerge from the micro-level interactions of the agents. A crime activity simulation could include multiple agents with varying levels of criminal intent, different routine activities patterns, and varying patterns of past criminal activity. Agent-based models require questions about what produces the ‘where,’ the ‘when,’ the ‘what,’ and the ‘why’ of crime. Development of multi-agent models requires a careful consideration of the interaction of individuals in different sites and situations. It begins with the premise that the world is dynamic, not static, and understanding activities and actions-including crime-calls for looking at agents at a micro level, exploring how individuals interact; how the urban backcloth of activity nodes, roads, transit, social variability, and routines influence interactions. The macro is formed by aggregating from the micro. Macro patterns are more easily understood when they are seen as the result of micro actions, aggregated. 4 figures, 24 notes