Growing up with a psychiatrist for a father (and a social worker for a mother) could be interesting. I often turned to my father for advice in the same way that any daughter would, but the results could be far from typical. The responses I got might be psychological, as when my parents grounded me, and I couldn't go to some event that weekend that I had wanted to attend. I was upset, but my father corrected me: "You're not actually upset. You subconsciously sabotaged yourself in order to get grounded because you didn't really want to go." Or the physician in him would become more prominent: "You're not actually upset. Your blood sugar is low. Eat a doughnut." As both my father and I grew older, the advice evolved too, becoming more spiritual. We were eating lunch together one day when I revealed my fears about being in my mid-30s and not yet being married or having children. I wanted a family very much, and the lack of it troubled me. With a kind, empathetic smile, my father replied: "Don't worry. You've borne hundreds of children already. You've already been a mother many times, so it really doesn't matter if in this life you are one. Right?" Then he stood up and washed his plate, as if there were no more to it. It was all so clear in his mind; from his experience and vantage point, he could practically see the string of lifetimes I had lived before this one and will live after it, the faces of my many children grinning happily at him. I already had had all those kids; why worry about another one or two? To him, there is truly never any reason to worry, to fear, to grieve. He is right, of course, and I knew that, but the earthly me sitting there at the table, still eating my sandwich, still longing for love, felt less than convinced.

People often ask us what it was like to write a book together, as we recently finished co-authoring Miracles Happen: The Transformational Healing Power of Past-Life Memories. This is an understandable question, as any parent-child team working together can find itself stepping cautiously through minefields, regressing into old, unhealthy dynamics and patterns. Yet I can say with all honesty that it was one of the smoothest, easiest experiences of my life. When we started the process, my father would write by himself, and I'd take the pages once he was finished, editing them and weaving them together, adding my own thoughts and reflections. I loved reading his handwritten notes, dotted here and there with profound insights that gave me pause, poignant sentences that gave me goose bumps, and silly jokes that gave me giggles. I would call him and ask him what he thought about changing one thing or another, and he wouldn't even need to hear what it was I was suggesting, trusting me fully and unconditionally, valuing me as a professional, a colleague, and not merely a child. At other times, the magic could only happen when we were together. It would be a process, starting with one idea and working off each other until the next appeared, and then a new idea, the right one, would form as we spoke, processed, debated. There was never an argument or disagreement. Before our writing sessions, we met for breakfast at a local deli, filling up with a good meal and lots of coffee. As we ate, we discussed things like free will and destiny, soul mates, the law of attraction—your typical father-daughter breakfast conversation—and then we'd go to my house. In a room overlooking my garden, we sat in chairs next to each other, my cat sprawled at his feet, the computer in my lap, and wrote together. My father had been doing past-life regression work for so long that he would often raise an incredibly compelling thought or insight and then move on. I, who was far newer to it, would want more information about these things that I hadn't yet seen for myself or hadn't yet understood the mechanisms of as well as he did. "When does that happen?" I would ask, speaking for myself as well as our potential readers. Or, "How?" Or, "Why? Under which circumstances? What do you mean by that? Is that true for everyone?" and so on. My father would begin to explain it to me, and as we would probe the issue together, unpacking these concepts and beliefs, asking and answering questions of each other, I would write his words down, and our dialogue would eventually become the basis for a new passage, a new teaching. I would start a sentence, and he would finish it, or vice versa. Our words and thoughts met, touched and melded together. There was no minefield, only a dance floor.

We were working on a chapter about animals and the lessons they teach, trying to come up with a few paragraphs to introduce the idea. Looking out the window onto the garden, I could see a tiny hummingbird landing on a feeder. "A hummingbird..." I said. My father observed the bird drink and flit about happily. "Sips the nectar of life, reminding us to taste its sweetness," he answered as I typed his words in. "What about dogs? What do dogs teach us?" I asked, and he spoke of unconditional love and loyalty, and that too went into the book. For over a half an hour, we thought of all kinds of different animals, different lessons, trading thoughts back and forth, building on each other's words, clearly having fun with this exchange of ideas. At one point, my father turned to me and gently said, "How long are we going to continue with this?" The paragraph had taken over the pages; we were simply having a good time and had forgotten that we were supposed to be writing a book. Another time, in an otherwise philosophical passage about the essence of a soul, my father inserted an absurd and nonsensical joke about ghosts and suggested that we keep it in the manuscript to see if our editor would question it, wondering if perhaps we could sneak it through each draft all the way to publication. (Anyone who has met my father knows that under that calm and composed exterior lies a wickedly dry sense of humor.) He would never have actually allowed this; he takes his work and his books very seriously, knowing just how life-changing and healing it can be. Perhaps because of this, I laughed so hard that I could not stop crying and had to take a break to compose myself. I still smile when I think about it. This kind of laughter happened countless times throughout the writing process. The entire experience was joyful.

Of course, there are bumps on the proverbial and literal road, as I found out when we embarked on our book tour together. A man at a New York event asked what the book was about, and I answered that it was a nonfiction book about past lives. "Don't you mean fiction then?" he responded with a pointed look. Being Dr. Weiss' daughter necessarily means that I am also his defender, his representative, not merely of him but of his entire belief system, regardless of whether I am in the mood to be. I am his guardian too, far more protective of him and of what people say to and about him than he would ever be of himself. After all, that's my dad. There were long flight delays, strange cities, dinners inhaled near midnight after book signings that ran late. Yet there were also exhilarating presentations, beautiful souls to meet along the way, afternoons spent exploring places we'd never been. An adult does not always get to spend a great deal of quality time with her father, but through the book I did, and as we traveled across the country, I collected our hours together like souvenirs. We'd wheel our suitcases throughout the terminal after weeks of long, sleepless nights, discussing whether his basketball team would make the playoffs, how evil occurred in the grand scheme of things, if he needed more shampoo, why children died. We spent hours having profound conversations about the very nature of human existence; we spent hours playing a word scramble game on my phone. One experience was no less important than the other.

The last 40,000 years I have spent with my father have been wonderful, and now we've added 33 more to the tally. It's impossible to say what the next 40,000 might look like, whether we'll continue to choose the same roles as parent and child, or reverse them, or take on new ones entirely. Maybe he'll be the hummingbird and I'll be the dog, and we'll spend our days together in a garden, sipping sweetness and loving unconditionally. Will we spend them here on Earth—will there be an Earth then? Will we find ourselves in another world, another dimension entirely? A higher plane of being, of existence, as we continue to evolve through the years? Will we choose to forgo physical form and stay on the other side instead, loving each other at the level of spirit, far beyond any bodies, any false distinctions such as "father" and "daughter"? I do not know. All I know is that, while there may have been a beginning to our relationship, a time thousands and thousands of years ago when our souls first met, there will never be an end, for there is no end to soul. There is no end to time. And there is no end to love.

More from Dr. Brian Weiss and Amy Weiss
The lesson Amy Weiss learned from her past life

4 things you didn't know about past-life regression

Telltale signs you might have had a past life