Teasdale had found himself spiritually challenged by the political turmoil of 1960s America, having the effect of plunging him into a spiral of reflective turbulence which lasted three years. While a student at a small catholic college, he started visitingSt. Joseph's Abbey, a Cistercian monastery near Spencer, Massachusetts. Here he came under the spiritual direction of the then abbot, Thomas Keating, a founder of the centering prayer movement. Teasdale received a masters degree in philosophy and later, in 1986, got a Ph.D. in theology from Fordham University. His dissertation was on the theology of the Benedictine monk Dom Bede Griffiths, who had lived much of his life at an ashram he'd founded in southern India. Teasdale went on to teach at DePaul University, Columbia College, the Benedictine University, and the Catholic Theological Union in Chicago, where he lived for many years. As a teacher, Teasdale formed lasting personal relationships with his students and became a mentor to many.

Following a correspondence with Bede Griffiths, a proponent of Wisdom Christianity, Teasdale decided to visit the Shantivanam Ashram in Tamil Nadu, and for two years lived at an ashram nearby. Inspired by Bede Griffiths' example, Teasdale became a Christian sanyassa, or renunciate in 1989. Teasdale formally took profession as a monk before Francis George, Archbishop of Chicago, in 2003.

Often he labored at various social causes, from environmental responsibility to homelessness, especially while he lived in Chicago. He participated in studies which explored the relationship between MDMA and mystical experiences, though of course he opposed drug abuse. He spoke quietly about how to benefit the human community. Often people would be affected by the kindness of his heart. He could also be funny and rollicking. Teasdale served the Parliament of the World's Religions by sitting on its Board of Trustees, where he worked with others in order to convene the centenary Parliament of 1993 in Chicago. This event brought together eight thousand people of many different faiths worldwide; out of it came the Guidelines for a Global Ethic.

Devoted to a new interfaith understanding, Teasdale came to espouse what he termed interspirituality, a perspective that discovered in the world religions a degree of commonality which could be approached through mystical experience. Teasdale was active in promoting and developing this facet of spirituality.

He associated with several contemplative and interfaith groups, including the Hundred Acres Monastery in New Hampshire (his resident address for several years), the North American Board for East-West Dialogue, andCommon Ground . Teasdale also was coordinator of the Bede Griffiths Trust. He became well acquainted with the Dalai Lama. As a member of the Monastic Interreligious Dialogue, he assisted the Dalai Lama Tenzin Gyatso and others, including the Cistercian Thomas Keating (mentioned above), in negotiating the text of the Universal Declaration on Nonviolence (1990), which sought to further the Satyagraha ideals established by Gandhi.

The Synthesis Dialogues has sponsored several conferences for selected religious and secular leaders, which aimed at increasing dialogue between faiths and at discerning how such interspiritual cooperation could benefit human affairs in general. Teasdale worked with the group initiating the dialogues. He can be seen and heard at a 1999 synthesis conference in Dharmsala, centered on the Dalai Lama, in the documentary Dalai Lama Renaissance.

In 2002, Brother Wayne, with friends and colleagues, founded Interspiritual Dialogue (ISD), an NGO accredited by the United Nations Department of Public Information. After Wayne's transition in 2004, ISD expanded internationally to become Interspiritual Dialogue 'n' Action. This network works to promulgate Brother Wayne's vision of interspirituality and the Interspiritual Age. In 2008, ISDnA, the Common Ground Conferences and other friends of Wayne partnered with One Spirit Learning Alliance and Interfaith Seminary in New York City to form a core educational program based on Brother Wayne's work and that of the Integral thinkers like Ken Wilber and Don Beck. A centerpiece of this program has been articulated by Drs. Gorakh Hayashi and Kurt Johnson, colleagues of Brother Wayne, in The Heart of Brother Wayne Teasdale's Vision of the Interspiritual Age. (Vision in Action, 2008).

In 2009 ISDnA created the extensive educational website "InterSpiritual Multiplex: A Guide and Directory to InterSpirituality Worldwide" [1]. In 2010, ISDnA partnered with the Order of Universal Interfaith and the World Council of Interfaith Congregations [2] to create, with some one hundred founders including many friends of Teasdale, The Universal Order of Sannyasa, as association of interspiritual contemplatives and sacred activists envisioned by and spoken of by Teasdale in all of his books. Soon after its January 2010 founding, the name was modified from The Universal Order of Sannyasa to "Community of The Mystic Heart, an Interspiritual Circle of Mystics and Contemplatives originally envisioned as the Universal Order of Sannyasa by Bro. Wayne Teasdale" [3].

The purpose of the community (established as a religious order and able to ordain "Interspiritual Ministers" and "Wisdom Keepers") fulfills Teasdale's vision of an active international association dedicated to spiritual life practice, sacred activism and advancement of the interspiritual message. Kurt Johnson became the first Administrator serving a circle-style leadership including numerous persons associated with Bro. Teasdale during his life's work.

Teasdale died of cancer in 2004.

Books

• Essays in Mysticism: Explorations into Contemplative Experience, Forward by George A. Maloney (Liturgical Publications/Sunday Publications 1982) ISBN 0941850021
• Towards a Christian Vedanta: The Encounter of Hinduism and Christianity according to Bede Griffiths (Asian Trading Corporation 1987) ISBN 8170861225 Developed from his dissertation at Fordham University.
• The Mystic Heart: Discovering a Universal Spirituality in the World’s Religions, Forward by the Dalai Lama, Preface by Beatrice Bruleau (New World Library 1999) ISBN 157731140X
• A Monk in the World: Cultivating a Spiritual Life, Forward by Ken Wilber (New World Library 2002) ISBN 1577314379
• Bede Griffiths: An Introduction to his Interspiritual Thought, Forward by Bede Griffiths (Skylight Paths Publishing 2003) ISBN 1893361772
• Catholicism in Dialogue: Conversations across the Traditions (Rowman & Littlefield Publishers 2004) ISBN 0742531775
• The Mystic Hours: A Daybook of Inspirational Wisdom and Devotion (New World Library 2004) ISBN 1577314727

Editor

• The Community of Religions: Voices and Images of the Parliament of the World's Religions, editor, with George Cairns (Continuum International Publishing Group 1996) ISBN 0826408990
• Awakening the Spirit, Inspiring the Soul: 30 Stories of Interspiritual Discovery in the Community of Faiths, editor, with Martha Howard, Forward by Joan Borysenko (Skylight Paths Publishing 2004) ISBN 1594730393

Articles

• "The Heart of Brother Wayne Teasdale's Vision of the Interspiritual Age" Vision in Action Spring 2008 (2008).
• "The Meeting of East and West: Elements of a relationship" Spirituality Today vol. 38 (1986).
• "Interreligious dialogues since Vatican II. The monastic contemplation dimension" Spirituality Today 43: 119-133 (1991).
• "Spirituality as a Primary Resource in Promoting Peace"

Audio

• Hermitage of the Heart: Contemplative Practices from Hundred Acres Monastery (2003 Sounds True) [Cassette] ISBN 1564559521

An opponent of the interspiritual view may argue that interspirituality compromises many of the basic tenets of certain world religions. A literalist interpretation of Christianity, for example, might assert that the Bible and the message of Christ found therein, directly contradict and expressly defend themselves against interspiritual interpretation.

Perhaps a closer scrutiny and understanding would foster a mild reply to such criticism of alleged "compromises"; counter-examples would include the following. The priest Melchizedek, to whom Abraham tithed; and Jethro, priest of Midian, father-in-law of Moses. Cyrus the Great, whom the Bible praises as anointed of God; and the three wise men who came from afar to behold the infant Jesus. Also pertinent is the evident influence of Greek philosophy on Judaism both before and after Christ, and its subsequent and continuing direct influence on Christianity. The teaching would include: that beliefs of the stranger or foreigner are not by dogma to be associated with ignorance or heathenism, but rather non-Christians are to be treated well, with love and respect (e.g., by following the golden rule); such a mandate calls for discernment: to follow the spirit and witness the true with integrity.