This threesome rediscovered a contemplative practice based on the 14th century text, "The Cloud of Unknowing" and tailored it for modern times. They eventually named it centering prayer, a type of non-conceptual, non-discursive, non-thinking based meditation practice. The practice has became widely adopted throughout the world.
Fr. William's passing is a significant closure and perhaps celebration of a chapter in the revival of contemplative spirituality and practice in the Christian world - as all three monks have now passed-on yet left behind a host of treasures. May all three rest in peace.