Christmas is always a time for me of joy but also a sense of wistfulness and reflection, because of the particulars of my own story.

My mother died four days before Christmas. We spent that grim last week of 1996 in her house in Florida, burying her, clearing out her possessions, tying up the hundreds of loose ends involved in ending a life.

Sifting through the flotsam and jetsam of her bedroom one afternoon, I spotted a small maroon keepsake box under the bed and uncovered, next to a pink baby album and a few faded early Polaroids, a bundle of all my letters home from college.

I opened a few of the multi-colored envelopes and sat back to read, in the loopy handwriting of my youth, a blow-by-blow account of my first year away from home at Northwestern University.  Amid a catalogue of imagined accomplishments —tacit reassurance to my parents of the soundness of their investment — one passage stood out: “Today, I am going to learn astronomy.”

I smiled, recalling this upstart younger self, but any amusement was quickly dispelled by the realization that my mother would never share this moment with me. She of all people would have immediately grasped my true meaning — I am going to take on all of astronomy in a single day — she who’d been so entertained by, so invested in this particular character flaw of mine, an early certainty that any behemoth across my path could be safely wrestled to the ground.

Today, I am going to learn astronomy. That line became a kind of catchphrase between my husband and I during the writing of The Field – and indeed of most of the books I went on to write. For a non-scientist like myself to take on this project began to seem no less preposterous than trying to swallow the whole of astronomy in a single gulp.

Christmas also brings up of memories of my Dad, whose birthday was six days before Christmas. My father, the bright youngest child of working-class Irish, was more an inventor than a straightforward engineer. At the end of the Second World War, he designed a revolutionary kind of heating system for all the new homes being built for returning vets.

In order to fund the start-up, he found two partners willing to invest. They would handle the sales and finance, while he would focus on the designs and shop floor. In a nod to the patriotic mood of the times, the three partners christened their new firm the ‘Federal Boiler Company.’

Dad’s business rapidly took off. He and my mother had moved from Yonkers and the Bronx to the pretty suburban town of Ridgewood, New Jersey. Year after year, they enjoyed the fruits of increasing prosperity: a speedboat, a second car, a second home.

By 1970, one partner had died and dad’s remaining partner was growing ill. The company began to founder badly. After the remaining partner died and my father took over, he discovered the reason: two sets of accounting books, the official one for my father, and another revealing the truth about the other two partners’ drawings.

Before the business got bought for a song, the hefty life insurance on Federal’s directors was still in place. The partner’s widow landed a million dollars, while my father, by then in his mid-fifties, had to find work among his company’s rivals. When I returned home from college one summer, the second car and house were gone, and the house in Ridgewood he and my mother had built from scratch was up for sale.

Dad never stopped believing that he could do it all over again. On a trip to Florida, he saw another problem that needed a solution – the damage done to small pleasure boats continuously kept in the water. My parents moved to Florida, where my father set to work designing an ingenious boat lift that would scoop boats up and out of the water with just a push of a button.

During a particularly stifling summer’s day, while welding one of the prototypes, he fainted. The welding rod in his hand fell on his face, killing him instantly. Unlike his old partner, he died without life insurance. The new policy he’d meant to sign that evening was sitting on his bedroom chest of drawers.

I think of the sadness of their final trajectory – my Dad’s early death at age 60, my mother’s death at 78, all the credit card debt my brother and I discovered she’d left without the cushion of much savings or any life insurance.

But perhaps the greatest sadness for me is that they never actually got to see who I was going to become.  My father was around when I landed my first editorial job in New York, and published my first big newspaper scoop, but he never knew that I would go on to write books.  He died before he could meet my husband Bryan or our two daughters or even What Doctors Don’t Tell You – or any of it.  He never lived to see the entire trajectory of my adult life.

And my mother, who did get to meet Bryan and her first granddaughter and witness the beginning of my professional life, never lived to see our second daughter, or even where life would take us, the sharp pivot I would take in my career to write The Field.

She never lived to see that I would indeed take on the whole of astronomy in one gulp – in this case, quantum physics and modern medicine. It would have made her smile.

But the spirit of both of them live on in me, the constant cheerleader of my mother, rooting for me to do what had been unavailable to her as a housewife in the 1960s. Or my Dad, providing the moral compass that always pointed to true north, whose early death when I was 25 spurred me on to never wait for a tomorrow that never comes.

I wish they had been around to celebrate a few more Christmases with us, but they are still here in me, continuing to shape the person I am and will be.

May you spend a moment this holiday season toasting your parents for setting you on your path, with all its joys and sorrows, all its strange turns and detours, that make up a life lived to the full.