Chapter 31 Computational Laboratories for Spatial Agent Based Models An agent based model is a virtual world comprising distributed heterogeneous agents who interact over time. In a spatial agent based model the agents are situated in a spatial environment and are typically assumed to be able to move in various ways across this environment. Some kinds of social or organizational systems may also be modeled as spatial environments where agents move from one group or department to another and where communications or mobility among groups may be structured according to implicit or explicit channels or transactions costs. This chapter focuses on the potential usefulness of computational laboratories for spatial agent based modeling. Speaking broadly a computational laboratory is any computational framework permitting the exploration of the behaviors of complex systems through systematic and replicable simulation experiments. By that definition most of the research discussed in this handbook would be considered to be work with computational laboratories. A narrower definition of computational laboratory (or comp lab for short) refers specifically to specialized software tools to support the full range of agent based modeling and complementary tasks. These tasks include model development model evaluation through controlled experimentation and both the descriptive and normative analysis of model outcomes. The objective of this chapter is to explore how comp lab tools and activities facilitate the systematic exploration of spatial agent based models embodying complex social processes critical for social welfare. Examples include the spatial and temporal coordination of human activities the diffusion of new ideas or of infectious diseases and the emergence and ecological dynamics of innovative ideas or of deadly new diseases.