Should Christian theology be interested in mysticism? A strong current within contemporary theology believes it should be, linking up with an older tradition holding that the mystical dimension has always formed the deepest current in the flowing river of Christianity and its theologies and doctrines, even if some have failed to recognize that. This article explores this modern current, its “founders,” its motivations, the questions it raises, and its accomplishments. Mystics are acknowledged as witnesses to the originary experiential source of Christian doctrine and theology. These modern pioneers explore possibly constant features of the mystical element, and emphasize the “turn to experience” as a central feature. The contemporary discussion has moved in the direction of exploring as holistic a view of experience as possible, stressing its constructed nature, and employing a lexicon emphasizing consciousness, practices, participatory awareness, and performative utterances. One typically thinks of mystics who have written classic articulations of their journey as “the” mystics. This is natural, as these writings are the time-tested paradigms that have founded the science of mysticism. But might one be a mystic whose form of expression occurs through art, or through the prophetic struggle for justice, or simply through the humble and often unnoted life of selfless love? Perhaps most mystics remain unknown! All forms of Christian mysticism are related to Jesus but take varying forms: a kingdom-centered and Father-centered focus, echoing somewhat the liberating focus of Exodus and the Gospels; a Logos mysticism, who indwells believers and whose indwelling unites all disciples (John 17:20–24); a spousal mysticism, echoing the bride and bridegroom theme in scripture (Hos 2:16–20; Mark 2:18–20; John 3:29; Eph 5:23–33). Paul’s letters are a treasury of participative mysticism (koinōnia), celebrating fellowship with fellow disciples in the body of Christ and being “with” and “in” Christ (1 Cor 10; Rom 6). As the trinitarian belief and doctrine gain clarity, one increasingly comes upon a more trinitarian style of mysticism (e.g., the Rublev Trinity icon). The relationship between theology and mysticism appears to be mutual: Christian sources and beliefs influence theology, but the mystical vivid experience of God’s presence keeps belief and doctrine anchored in a rich experiential soil. But it is suggested, by way of a heuristic for further exploration, that this mutual, back-and-forth interplay between mysticism and theology or doctrine is asymmetrical as well. That is, mysticism may be thought of as the originary and even paradigmatic source of theology (and formal doctrine). This would echo an older tradition voiced, for example, by Evagrios in patristic times and Vladimir Lossky and Karl Rahner in modern times. One way of understanding this would be to begin with the phenomenon of spirituality and to view mysticism as spirituality’s radically transformative expression. Spirituality derives from the work of the Spirit, who renders our life “Spirited” (1 Cor 2:15). Spirituality can take on a range of theological and doctrinal forms, as the human faculties needed for this are gradually enriched and transformed by the Spirit. At times the mystics become paradigms of theology and doctrine, through the radical transformation of consciousness and action. An important by-product of this model is that theology and spirituality are never really separated. When one begins to think in this separationist way, it is a signal that one’s experience and understanding are suffering from a certain narrowness and distortion. Finally, Christian mysticism and theology (along with doctrine) have been and are continually challenged by seismic transitions in human history, as is Christianity in general. These are never really left behind, even when their challenges are more or less successfully met. At best one can build on them and continually seek to integrate their enduring lessons. The key transitions that the mystic is challenged to learn from and integrate include: “primary”/cosmocentric challenges; biblical; Classical; sapiential; Far Eastern; Muslim; medieval; Renaissance and Reformation; modern; late modern; postmodern; globalization; neocosmocentric; and ecological challenges. The traditional mystic stages and states, for example, will undergo important transformations as they pass through these various transitions. To the extent that the mystics meet these challenges, they become the paradigmatic theological explorers and guides for the rest of us on our journeys.