He trained as an analyst at the Jung Institute in Zurich, where his principal analyst was Emma Jung, wife of the psychiatrist Carl Jung, who had originated the concept of the shadow decades earlier.

Back in the United States, he began writing short books on Jungian ideas for general readers rather than clinicians — He, She, and We among them — building a following well beyond the analyst's couch.

In Owning Your Own Shadow, published in 1991, he argued that whatever we refuse to see in ourselves doesn't vanish — it gets projected onto others instead — and that the shadow holds buried gifts, not only faults.

He died in 2018, having spent nearly seventy years turning Jung's clinical language into something a reader with no training could pick up and use on their own life.