There is an instinctive drive among all humans to make meaning of their daily lives. Because there are no enduring truths, and change is continuous, people cannot always be assured of what they know or believe. It therefore becomes imperative in adulthood that they develop a more critical worldview as they seek ways to better understand the world. This involves learning "how to negotiate and act upon their own purposes, values, feelings and meanings rather than those they have uncritically assimilated from others." Developing more reliable beliefs, exploring and validating their fidelity, and making informed decisions are fundamental to the adult learning process. It is transformative learning theory that explains this learning process of constructing and appropriating new and revised interpretations of the meaning of an experience in the world. This chapter updates transformative learning theory through discussing emerging alternative theoretical conceptions, current research findings, and implications for practice.