Within months of Adolf Hitler’s rise to power in 1933, the Jewish-German educator Anna Essinger devised an escape that would take her and her Jewish students and staff out of an increasingly repressive Germany. Under the pretense of a school trip, they divided into small groups, each traveling on its own schedule by train across the border and out of reach of the Nazis. Their destination was Bunce Court, a ramshackle 17th-century country estate in Kent, England, that would serve as their new school. There, over the course of the next 15 years, more than 900 traumatized and orphaned children would receive refuge and care and have a place to call home.

In “The School That Escaped the Nazis: The True Story of the Schoolteacher Who Defied Hitler,” the British author and BBC television producer Deborah Cadbury provides a persuasive portrait of Essinger (1879-1960) as a lesser-known heroine of the Holocaust and someone who deserves broader recognition.

Born in Ulm, Germany, Essinger was the oldest of nine children. At the age of 20, she accepted an aunt’s invitation to join her in America and eventually enrolled at the University of Wisconsin, where she received her master’s degree in education. During her stay in America, she became so drawn to the humanitarian values of the Quakers that at the conclusion of World War I she joined a Quaker relief mission and returned to Germany as a liaison officer in charge of organizing hundreds of school kitchens to feed hungry children.

That work gave Essinger experience in school administration and inspired her to open a new kind of school, one that rejected old-fashioned autocratic, punitive methods in favor of the more flexible, child-centered philosophies being developed by progressive educators such as Maria Montessori and A.S. Neill. In 1926, with the help of her siblings, Essinger opened a boarding school in the village of Herrlingen. She soon garnered the nickname Tante Anna, reflecting what one student called her “authoritarian but very motherly” presence. The school’s egalitarian atmosphere, and its ethos honoring the dictum “love one another and if that is not possible, at least respect each other,” stood in stark contrast with Nazi ideology.

By the time Essinger fled Germany less than seven years later with about 70 of her students and half of her staff, Jews had already been banned from Germany’s public schools, Jewish books were being publicly burned and Essinger herself had come under Nazi suspicion for her progressive methods. Yet many in Britain were still not aware of Hitler’s repressive, anti-Jewish policies.

By contrast, when Essinger approached her students’ parents about allowing their children to leave Germany and flee to England with her, most immediately said yes. From their vantage point, the plan would provide their children with an immediate escape from the escalating levels of anti-Semitic persecution and buy additional time for the parents to arrange the rest of the family’s departure from Germany. With borders closing, however, there was often not time enough; many of Essinger’s students never saw their families again.

Upon arriving in England, Essinger was dismayed by the lack of care or appreciation among British educators for the Bunce Court School’s severely strained budget. School inspectors rebuked Essinger for the building’s lack of electricity, insufficient heating, inadequate plumbing and inferior kitchen facilities. They also puzzled over the school’s communal, family-like atmosphere, clueless that emotional warmth might help mitigate the students’ homesickness.

Their official reprimands were a blow. Essinger desperately needed the inspectors’ stamp of approval to attract additional students—especially fee-paying British students who could assist Bunce Court financially. Undaunted, Essinger rallied her staff, and together they devoted their weekends and off-hours to remedying their facility’s many structural problems, reconfiguring the drafty building into more functional classrooms and dormitories, and clearing land for playing fields. They also repaired the greenhouses and planted vegetable gardens whose bounty would supply the kitchen. As an added touch, they even created an open-air amphitheater and produced theatrical productions to which they invited the public. Bunce Court soon received its accreditation.

Then in November 1938 came Kristallnacht, the violent Nazi-incited attack on Jews throughout Germany. In response, an international rescue operation organized the Kindertransport to bring more than 10,000 Jewish youths to England from Austria, Czechoslovakia, Germany and Poland. A number found their way to Bunce Court, where the school’s prevailing tone of restraint and understanding, combined with the camaraderie and mutual support found among the students, helped soothe the sense of displacement and uncertainty among the new arrivals. Anticipating the possibility that some newcomers would lash out in anger, Essinger trained her staff to respond with kindness. When one student, prone to temper tantrums, spat angrily in his teacher’s face, the teacher told him: “Yes—go ahead and spit. Let everything out.” He did, again and again, until he began to weep uncontrollably; afterward, as if purged of anger, he let his teacher console him and never flew into another rage.

In the years following the war, and until its closing in 1948, the Bunce Court School continued to offer support to displaced, uprooted and orphaned children by welcoming the young survivors of the Holocaust. One “refused vegetables because they reminded him of the grass that he had had to eat to survive.” Another had come to see himself as a “savage,” suspicious of any act of human kindness. Essinger’s patience and willingness to listen without judgment helped reorient them to their own humanity.

With her mix of idealism, pragmatism, determination and hesed—the Hebrew word for loving kindness—Anna Essinger continues to set a compassionate example as we go about healing the newest generation of traumatized youths.

Ms. Cole is the author of the memoir “After Great Pain: A New Life Emerges.”