In 1970, Sunnie D. Kidd coined the term in-betweenness to conceptualize the mystery of interconnectedness of all beings. In-betweenness is the web that connects the cosmos and everything in it. It is, on a smaller scale, the nervous system that connects our universe and holds it together. In-betweenness is a shared resonating spiritual field of movement and vibration, which is the root of all spiritual experiences and scientific investigation. It is the common ground of all religions, which has been called the primordial om, akasha, prana, the quantum field, the music of the spheres, and the thumbprint of God. In-betweenness can be experienced on the personal scale as a shared spiritual dimension that connects us to everyone and everything else. This is the same field of energy that saints, mystics, Buddhists, yogis, priests, shamans, and seers have experienced by looking within themselves. In-betweenness is unseen and unheard, yet it is deeply experienced in interpersonal relationships where authenticity characterizes the way that two or more persons are together. In the heart of in-betweenness, two or more persons spiritual dimensions intermingle and a new dimension emerges in each that did not exist prior to coming together in this way. This shared spiritual dimension is a central energizing quality and provides a sense of protection, support, and caring. The new dimension that emerges involves an infinite spiritual dimension where participating people are enabled to go where neither alone could go. Each person in the relationship takes the other person forward in life. Through both good and bad times and together, they enjoy an interpersonal transcendence that enlivens, enriches, and engenders compassion, care, and solicitude. The spiritual dimensions in each person resonate, harmonize, and reverberate together and, in so doing, set up a resonant field of dynamic unity within where each person finds empathy, understanding, and deep care. The interpersonal transcendence frees each person to more fully be oneself. It encourages each person to learn more, and while comprehension grows, understanding and empathy deepen. The liberating quality found in in-betweenness opens new possibilities for each person and is given back mutually so that each brings the other forward. When taken altogether, the qualities found in this way of beingas oneself with the other and as a part of the other in an essential and meaningful waycontinue to develop, deepen, and grow until one person in the relationship is gone. If one person is gone, a part of oneself is experienced as being gone. This is the dimensional arc of in-betweenness.