With no advance notice, the billionaire’s representatives launched a flurry of emails and telephone calls this year to unsuspecting colleges and universities across the country dedicated to serving large numbers of Black, Latino and Native American students.

In early October, one such message reached Harold L. Martin, chancellor of North Carolina A&T State University, the nation’s largest historically Black university.

Martin called back and found a person speaking on behalf of a donor who wanted to make a special gift. The chancellor was pleased. He had just landed a record $5 million donation in September and hoped this one might be comparable, to benefit a school with 12,000 students.

Then he learned the donor wanted to give nine times that much. Then he heard the donor was one of the world’s richest people: author MacKenzie Scott. Then he heard, shockingly, there were no conditions on the use of the money. Scott, whom he had never met, trusted that the North Carolina A&T leadership would know what to do.

A few weeks later, $45 million landed in the university’s account.

“We all just went berserk with joy,” Martin recalled last week in a Zoom interview.

That was just one of Scott’s bolt-from-the-blue gifts, some revealed in July and many more Dec. 15. In all, a Washington Post tally found, she has delivered more than $800 million to a collection of schools, public and private, that are almost entirely unaccustomed to that level of largesse. That historic sum includes more than a half-billion dollars for historically Black colleges and universities.

It is part of Scott’s wider initiative to give nearly $6 billion this year to charitable and social causes from a fortune that Bloomberg News estimates to be about $60 billion.

Scott’s ex-husband is Amazon founder and chief executive Jeff Bezos, who owns The Post.

The magnitude and method of Scott’s giving has turned higher-education philanthropy upside down. She isn’t interested in putting her name on campus buildings. She isn’t dictating an academic or research agenda. The schools she identified as recipients are, for the most part, not the usual suspects. They are neither in the Ivy League nor in other educational circles that tend to cultivate, attract and sustain big wealth over generations.

Scott, in announcing her donations on the website Medium, wrote that she and her team wanted “not only to identify organizations with high potential for impact, but also to pave the way for unsolicited and unexpected gifts given with full trust and no strings attached.” She did not specify how much she gave to each of the 42 colleges and universities listed as recipients this past week and in late July.

Many schools revealed the sums themselves. The Post found those disclosed gifts totaled $842 million.

Of that amount, $147 million went to Hispanic-serving institutions, $5 million to tribal colleges and $560 million to historically Black colleges and universities. In addition, a total of $130 million went to five other public colleges in Florida, Washington state, Nebraska and Kentucky.

Unspecified amounts went to a handful of tribal colleges and universities that serve Native Americans, from Navajo Technical University in New Mexico to Salish Kootenai College in Montana.

HBCU advocates were overjoyed not only at the amount of money but also at the vote of confidence in their work.

“It’s money going to institutions that have been doing a lot of hard work for a long time and never gotten this kind of at-one-time support,” said Michael Lomax, chief executive of the United Negro College Fund. “The donor is saying: ‘I believe so much in what you are doing. I respect so much your work, that you use it as you see fit.’ ”

“It is a huge deal,” said Harry Williams, chief executive of the Thurgood Marshall College Fund. In recent times, he said, there is almost nothing to compare to Scott’s HBCU philanthropy. “Transformational,” he called it.

UNCF and the Thurgood Marshall fund provide scholarships and other support to students who attend HBCUs. Scott gave the two funds major gifts as well, but Lomax and Williams declined to specify how much.

Spelman College, a school for Black women in Atlanta, received $20 million from Scott. Mary Schmidt Campbell, president of the college, read the billionaire’s message this way: “You know what you are doing. You do it well. I am affirming that.”

For HBCUs, Campbell said, it has been a long time coming. “This is a sector that has been working for 150 years, in some cases almost completely without that affirmation,” she said.

Some historically Black colleges have drawn major philanthropy. Spelman was named for the wife of oil magnate John D. Rockefeller in the late 19th century as he gave the school crucial donations during its founding period. Morehouse College, a neighboring school for Black men, was the recipient of a major gift in 2019, when billionaire Robert F. Smith pledged $34 million to pay off the education loans of that year’s graduating class.

In June, Netflix chief executive Reed Hastings and his wife, Patty Quillin, announced gifts totaling $120 million, divided equally among Morehouse, Spelman and UNCF. That money will fund student aid in what the couple said was an effort to encourage further philanthropy to reduce racial inequities. Billionaire Mike Bloomberg announced in September a gift of $100 million to four historically Black medical schools.

Scott’s donations to HBCUs range from $4 million to tiny Voorhees College in South Carolina, which had 510 students in fall 2019, to $50 million to Prairie View A&M University in Texas, which had 8,940.

Howard University in D.C., Morgan State University in Baltimore and Norfolk State University in Virginia each received $40 million — a record-smashing sum for all three.

Ruth Simmons, president of Prairie View A&M, knows big-time philanthropy well. She once was president of Brown University in Rhode Island, which now has an endowment of $4.7 billion. She recalls a donor who gave $130 million to Brown during her tenure — a major development, to be sure, but on a scale hardly unknown in the Ivy League.

By contrast, Prairie View A&M’s endowment stood at about $94 million at the time of Scott’s gift, Simmons said. The school’s previous record donation was $2.1 million.

Simmons plans to use much of the Scott gift to raise the endowment to $130 million. She also will channel some of it to students whose families are suffering financially because of the coronavirus pandemic. At North Carolina A&T, Scott’s gift will, among other things, help the university compete for highly qualified students, support those in financial need and deepen its academic offerings.

Simmons said Scott has broken what had become a troubling pattern in education giving — of the rich getting ever richer — a perennial trend that reinforces racial inequities.

“There’s a long history in this country with minority institutions being underfunded, being thought of as not competing with White institutions, and therefore not receiving adequate funding to do the work that we do,” Simmons said. She called the Scott gifts “epic.”

Elsewhere in Texas, Scott delivered big to schools with large Latino populations. Palo Alto College in San Antonio, a two-year public school with 10,000 students, more than three-quarters of them Hispanic, confirmed last week that it received $20 million.

“It’s hard not to get a little emotional,” said Robert Garza, the college’s president. “Major institutions tend to get these very large gifts and they go into their billion-dollar endowments that they already have. Community colleges don’t get these opportunities.”

Garza said the gift will help the school provide more scholarships and draw more students into higher education. “This gift really amplifies our ability to really reach out to the community from day one to start having conversations about college,” he said.

At tribal schools, mega-gifts are rare but desperately needed.

“We are prolific grant writers. We work hard because that’s what we have to do,” said Sandra Boham, president of Salish Kootenai in Pablo, Mont., which has about 700 students, mostly Native Americans. “You’re always chewing your fingernails, hoping that your budget’s going to balance, hoping you can continue doing the work you need to do.”

Boham said Scott’s gift ran into seven figures, the largest single-donor donation in the school’s history. The school will use it to expand professional development for employees and invest in campus housing. Scott’s donation will also fund scholarships that Boham hopes will help the college attract and retain students. “This gift, I can’t even tell you the significance that it brings to us,” she said.