We review and expand several perspectives on the relationship between knowing and "not knowing" (or openness) and three core practices of not knowing: (1) in mindfulness practice; (2) in listening to others (and oneself); and (3) in challenging transitional phases of one's life, when significant concerns in one's life are not resolved or clear. In the context of the third type of practice, we explore the "Dark Night," first named by the Spanish mystic, Saint John of the Cross (1542-1591), which may be briefer or longer, in terms of some of its dynamics and some suggestions on how to work with it.