The Human Connectome Project (HCP) aims to delineate the typical patterns of structural and functional connectivity in the healthy adult human brain. Individual differences in these patterns are significant and are associated with variations in cognitive and behavioral variables that affect real-world function. The HCP is collecting behavioral measures and using task-fMRI (tfMRI) to explore the relationship between individual differences in neurobiological substrates and both functional and structural connectivity. This paper outlines the rationale and development of the behavioral, individual difference, and tfMRI batteries, providing preliminary data on activation patterns at both group and individual levels. The HCP's goal is to understand how variations in brain connectivity contribute to neurological and psychiatric disorders, which collectively incur a substantial economic burden. The tfMRI battery includes tasks that help identify "nodes" in neural systems, validate functional areas, and relate activation patterns to individual differences in performance and traits. The paper details the design considerations, pilot testing, and specific tasks used in the HCP, emphasizing the efficiency and broad range of neural systems assessed.The Human Connectome Project (HCP) aims to delineate the typical patterns of structural and functional connectivity in the healthy adult human brain. Individual differences in these patterns are significant and are associated with variations in cognitive and behavioral variables that affect real-world function. The HCP is collecting behavioral measures and using task-fMRI (tfMRI) to explore the relationship between individual differences in neurobiological substrates and both functional and structural connectivity. This paper outlines the rationale and development of the behavioral, individual difference, and tfMRI batteries, providing preliminary data on activation patterns at both group and individual levels. The HCP's goal is to understand how variations in brain connectivity contribute to neurological and psychiatric disorders, which collectively incur a substantial economic burden. The tfMRI battery includes tasks that help identify "nodes" in neural systems, validate functional areas, and relate activation patterns to individual differences in performance and traits. The paper details the design considerations, pilot testing, and specific tasks used in the HCP, emphasizing the efficiency and broad range of neural systems assessed.