To conduct an intelligence analysis (IA), analysts perform multiple perceptual and cognitive tasks to understand the past, present, and/or future states of some real-world environment or situation, often employing abductive reasoning due to the significant degree of uncertainty characterizing the domains analysts operate in and the substantive problems they operate on. Although the tasks and cognitive processes that analysts carry out have remained relatively unchanged over the past half-century, research on the challenges, complexities, and constraints that make analyst sensemaking performance difficult has evolved, providing a better understanding of the key characteristics that define expertise in this field. This chapter highlights the unique characteristics of expert IA practitioners, compared to other domains. It highlights a range of past research characterizing the domain, from both a workflow perspective and an information processing perspective. Applying these characterizations, the chapter then highlights elements of expert behaviors that emerge throughout the IA process, and the implications of these elements on emerging research directions and the design of new assistive technologies to augment intelligence analysts executing modern and next generation IA.