When Khizr and Ghazala Khan took the stage at the Democratic National Convention in 2016 to condemn Donald Trump for the way he spoke about Muslims and immigrants on the campaign trail, they were speaking with the authority of Gold Star families. And when Mr. Khan brandished his copy of the Constitution and offered to lend it to the Republican nominee, now the president of the United States, he was doing more than that: He was making a wager on the quality of his own citizenship and love for America, a gamble he won when Trump responded with the first of a number of tantrums aimed at military families.

There’s no guarantee that a memoir by a person who suddenly becomes extremely famous will be any good. Especially if they’ve become famous due to a short speech or a viral moment, the question becomes whether or not they have anything more to say.

Khan, fortunately, does: “An American Family” is a small but lovely immigrant’s journey, full of carefully-observed details from the order in which Ghazala served tea at a university event, to the schedule of the police patrols in the Boston Public Garden where Khan briefly slept while he was in between apartments, to the description of Humayun’s headstone as a “slab of white marble with soft streaks the color of wood smoke.” And wisely, though the book includes the family’s decision to appear at the DNC and their preparation for that short, effective speech, Khan steers clear of Trump’s outbursts, which are clearly beneath his attention — and ours.

Most importantly, the book is an effective argument for the depth of Khan’s love for and knowledge of the Declaration of Independence, the Constitution and the amendments to it. He emerges as such an eloquent advocate for both documents, and for American values, that I finished “An American Family” with my own sense of patriotism and sense of civic obligation revitalized.

Khan first encountered our country’s founding documents in a law school class in his native Pakistan.

“The idea that people could simply announce they were taking charge of their own affairs was so bold as to be unimaginable. It had never occurred to me,” he explains. “The thing is, those truths were not remotely self-evident. Not to a young man in Pakistan and not to most people in the whole of human existence.”

America’s founding texts raised all sorts of questions for Khan. Why hadn’t other countries, including Pakistan, reached the same conclusions? Why did so many national constitutions lay out what the government could do, rather than limiting its powers? What insight had allowed Americans to treat their Constitution as a sufficiently living document that it could be amended?

Those questions didn’t translate into an abiding love of America until Khan began to meet actual Americans. This being something other than a typical immigrant narrative (Khan is very much aware of the genre’s cliches), those first encounters take place in Dubai, where Khan takes a job with an offshore oil drilling company.

There, he’s struck by the generosity and directness of the Americans he works with, who surprise him with company housing, help him get a license and buy his first car and introduce him to country music, including Ray Price, Conway Twitty and Johnny Cash. Americans are hardly the first or only people who behave this way: bookstore owners in Pakistan allow him to stand in the aisles and read books he can’t possibly afford, a professor at law school pays Khan’s exam fees for him, and a cab driver in Dubai takes him in when he at first has no place to live. But Khan is particularly struck by Americans’ reflexive desire to know and do good for each other.

“Were all Americans like this?” he wondered at the time. “Is this what the country, with its freedoms, wrought from rebellion, produced? Did a nation of laws, of equal dignity for all, instill in its people a basic goodness?”

The answer we know, of course, is no. An exception to the theory a younger Khizr Khan postulated is now president of the United States, and it’s because of that exception that Americans know who Khan and his family are today.

Still, there’s something appealing about being seen, both personally and as a country, through Khan’s eyes.

“I am an American patriot not because I was born here but because I was not,” Khan writes. “I embraced American freedoms, raised my children to cherish and revere them, lost a son who swore an oath to defend them, because I come from a place where they do not exist. I can perhaps see more clearly the blessings of America because they were once new to me.”

“An American Family” is a reminder to be grateful for our country’s well-paved roads and reasonably reliable bus schedules, our fractious political press and our chili dogs. It’s also an argument that the greatness of America is more than the presence of abundance that other countries lack, or the absence of repression that defines other regimes. For the Khan family, America was an active process that included taking in women who were fleeing domestic slavery in diplomatic households and an elderly veteran; cooking meals to take to homeless people who didn’t feel comfortable going to a shelter; and in Humayun Khan’s case, military service.

I closed “An American Family” feeling that Khizr Khan is probably a better American than I am. But it’s a strength of his book that I felt inspired, rather than condemned, by that conclusion. After all, the opportunities this country offers — whether it’s to enrich ourselves or to give back to the community — are available to us whether we were born citizens or applied for that status. It’s up to us when we get to work.