We all like certainty; we like to think we know. That’s as true in psychotherapy as in any other field. We want to have faith that our current clinical approach is solid, that our treatments work well, that our particular kind of presence in the room is healing to a client. And that may be true—as far as we know.

But that’s the thing: we can know only so much at any particular moment in time. The future is the ultimate blank slate. We have no way of knowing what vital insight about emotional healing we’ve missed thus far, or what new approach might work better. The story of psychotherapy is a chronicle of this law of limited knowing—and of the recurring appearance of creative leaps that push us beyond our established understandings. To delve more deeply into our shape-shifting history, we’ve interviewed seven longtime leaders in a range of clinical specialties, asking them to tell the story of their particular realm as it's evolved over four decades. These women and men were there, working in the trenches of their fields while alert to new possibilities. And so we asked them about it—about the original set of certitudes in their specialties, and what and who challenged them over the years, leading to the unfolding of fresh ways of thinking about, and doing, psychotherapy.

Change, of course, often breeds resistance. So our storytellers don’t flinch from describing the opposition that followed in the wake of new therapeutic ideas as well as the…