My question was much more about the term itself, than the concept it addresses and encompasses.
In Primitive Mythology, Campbell speaks of the trikster as a hero and the shaman as a representation of this archetype and stipulates the process of death and rebirth in much the same way as the 3 stages of the “Hero’s Journey”: Initiation, Separation and Return. It’s clear for me, the hero myth and his journey as metaphor for a self “journey” for a high consciousness level. The hero archetype is a key concepet on Jung’s theory and I have no doubt about the relation of Campbell’s Hero’s Jouney and Jung’s Individuation Process. In Campbell’s biography “A Fire in the Mind”, there is an account in one of his diaries, from 1937, if I’m not mistaken, where he makes an illustration with the archetypal pattern of the heroic journey, where he even represents the whale, or the whale belly, as a representation of the whole aspect of diving into the unconscious. In addition to references and approaches from the heroic journey perspective in relation to the work of Jung, Leo Frobenius, Van Gennep, Zimmer and several others, I particularly like the book
The Innateness of Myth: A New Interpretation of Joseph Campbell’s Reception of C.G. Jung” by Ritske Rensma, which articulates Campbell’s work in a much deeper way, than Robert Segal, for example.
But my curiosity was, really about, to know when the term “Hero’s Journey” starts to be used by Campbell himself, since, as Stephen well presented, he doesn’t even use the term in “Hero”.