As one of the five major personality traits, openness to experience has been established as a fundamental factor of personality. Yet its history, and what it constitutes, has not always been clear. This becomes obvious when observing how the label has changed over the decades: from Inquiring Intellect to Intelligence to Culture until finally the consensus of Openness to Experience. This final connotation denotes people who are flexible and receptive to all experiential possibilities. It is this flexibility that perhaps most defines open people and enables them to be creative, establish complex worldviews, and probe the depths of human experience. Therefore, open people not only see more possibilities but also engage with them. This chapter starts with a brief review of the history of openness to experience that leads into contemporary conceptualizations. It then moves on to discussing research on the trait’s associations with cognitive, perceptual, and behavioral outcomes. Finally, specific emphasis is placed on types of experience and how these may vary depending on people’s characteristics of openness to experience.