ATLANTIC CITY . Dad had a twinkle in his eye.

“Wait until you see this trick,” he told me. “This secret. You’re guaranteed to make money. I’ll show you when we sit down at a table.”

A blackjack table, he meant. Dad loves blackjack, especially with my three siblings and me, and we’ll circle a casino floor for an hour just to find a dealer with enough empty seats for three or four or all five of us, so that we can have our own little cabal.

He inducted us into the game decades ago, in Vegas, and we continued to play over the years, because it was another excuse and another way to spend time together: our ritual, our refuge.

Before last weekend, we hadn’t played in a long while. But for his 80th birthday, he got to choose the agenda for a weekend out of town. He picked blackjack. And he picked Atlantic City, because it was closer than Vegas and good enough.

It’s funny how modest his desires can be, given what a grand life he’s lived. He’s the American dream incarnate, all pluck and luck and ferociously hard work and sweetly savored payoff.

He grew up outside New York City, the oldest child of relatively poor immigrants from southern Italy. English was his second language.

He managed to be elected president of his high school over the blond quarterback from the right side of the tracks, then won a full scholarship to college. But first he had to persuade his parents that four years in New Hampshire at a place called Dartmouth could be as beneficial as an apprenticeship in a trade.

He married a grade-school sweetheart and stayed married to her through business school, a sequence of better jobs and a succession of bigger homes until she died at 61, just months shy of his retirement and of what were supposed to be their golden years. He eventually learned how to work the dishwasher, but never how to go more than a few minutes without pining for her.

It’s the phase of his life since my mother that I find most compelling, because it’s a tribute to what people are capable of on the inside, not the outside.

They can open up, soften up and step up. When Mom was around, my father’s assigned role in the family was as the stern disciplinarian . he played the warden, so that Mom could be our friend . and he was never forced to notice our hurts or attend to them, to provide succor and counsel in matters of the heart.

Then he had to, because he was the only parent left. He held my sister’s hand through her divorce. He made sure to tell me and my partner that our place in the family was the same as any other couple’s.

And his nine grandchildren, only two of whom my mother lived to meet, came to know him as their most fervent and forgiving cheerleader, ever vigilant, ever indulgent. Their birthdays are the sturdiest part of his memory. He never fails to send a gift.

A generous man from the start, he has somehow grown even more generous still, not just with items of measurable value but with those of immeasurable worth, like his time. His gestures. His emotions.

He has figured out what makes him happiest, and it’s doing the little bit that he can to nudge the people he loves toward their own contentment. It’s letting us know how much he wants us to get there. It’s being obvious about all of that and, in the process, bringing a smile to our lips, a twinkle to our eyes.

Here’s what happened, on this milestone birthday of his, when we finally found the right blackjack table and fanned out around him and it was time for his trick:He asked each of us . his kids, our life mates . to stretch out a hand. And into every palm he pressed two crisp hundred-dollar bills, so that our initial bets would be on him and we would start out ahead of the game.

“See?” he said. “You’re already a winner.”

That was it --- his secret for blackjack, which is really his secret for life, and has nothing, obviously, to do with the money, which we’re blessed enough not to need too keenly and he’s blessed enough not to miss too badly.

It has to do with his eagerness, in this late stage of life, to make sure that we understand our primacy in his thoughts and his jubilation in our presence. It has to do with his expansiveness.

I pray I learn from his secret. I hope to steal it.