Growing up as a Jewish youngster in interwar Germany could be idyllic — until, suddenly, it wasn’t.

For thousands of unlucky, un-chosen, and most decidedly un-Aryan youths, the joys of innocence, of doting parents, sibling rivalry, and a serene feeling about their tiny slice of the world, were snatched away and forever upended on January 30, 1933, the day Adolf Hitler came to power and began dismantling the Weimar Republic’s fragile democratic underpinnings.

Whether in cosmopolitan Berlin, a remote farming village, or an industrial center, these youths paid an incalculable price. Classmates turned on them, teachers were emboldened into shaming hostility, SA troopers attacked them on the way to yeshiva or sat menacingly in the rear of the synagogue during services, sports leagues booted them out, and music lessons or cultural excursions were canceled by cowering instructors.

Life got very small very quickly.

The parents of these untermenschen paid as steep a price. Their tastefully furnished apartments (often above the family’s shop) or expansive homes became refuges from fear, as Jewish mothers and fathers tried to cope with the gathering storm and buffer their children from its fallout. But even these familiar sanctuaries weren’t immune from the sudden, warrantless raids of brownshirts and bullyboys.

The careers of businessmen, merchants, academics, doctors, and tradesman soon collapsed under the flurry of Nazi edicts depriving them of citizenship, legal protections, and property rights. The Jews of Germany, approximately 505,000 out of a population of 67 million, of whom a proportionally high number had served the fatherland during World War I, were classified by the Reich as a race rather than a religion, and a wretchedly inferior race at that.

While Kristallnacht on November 9, 1938, stands as a flashpoint for the Nazis’ unremitting attacks on humanity and decency, some Jews realized the inevitable in real time, and fled with families and assets intact. More of them delayed but still managed to spirit their children out of the country while remaining behind and suffering the consequences. And still others tarried to the end, immobilized by fear or refusing to believe what they were witnessing. Many of these families perished together in the camps.

Six young Jewish men who made it out (most as teens, one an older survivor of Dachau) form the focus of Bruce Henderson’s “Sons and Soldiers: The Untold Story of the Jews Who Escaped the Nazis and Returned with the U.S. Army to Fight Hitler.” It is a stark but vivid recounting of their escapes to the United States; their new lives with relatives scattered mostly in big cities; their return to Europe as American GIs who witness the liberation of the camps; and their subsequent, often heartbreaking searches for family members and survivors.

The six — Victor Brombert, Stephan Lewy, Martin Sellig, Manny Steinfeld, Guy Stern, and Werner Angress — are far from household names. But they formed a tiny subset of the “Greatest Generation,” not by birthright, but rather by luck, pluck, and chutzpah. Their weapons, when they were finally issued rifles and sidearms after gaining citizenship and being declassified as enemy aliens, included exceptional language skills, a chilling understanding of the Nazi mind, and a survivalist’s cunning shaped by flights and resettlement adventures.

Henderson illuminates the highly productive and compelling efforts of this bespoke band of “Ritchie Boys,” so named for the approximately 2,000 Jewish refugees who trained at remote Fort Ritchie in mountains of Maryland to hone their counterintelligence skills. Many volunteered for Army service just after war erupted and had to fight their initial battles against the hostility of fellow enlistees and officers suspicious of their accents, origins, and purpose.

Their graduation gifts came in the form of self-assurance and sergeant’s stripes. Indeed, the baby-faced, blond-haired Angress, who years earlier had been chosen to the howls of his classmates as the perfect Aryan by a so-called phrenology expert sent by the Reich, performed so well he was promoted to master sergeant upon graduation, causing jaw-dropping reactions from grizzled, older veterans.

They did their jobs diligently, creatively, and with personal restraint, keeping revenge impulses well in check while confronting German prisoners who ranged from haughty to helpful. They did, however, exploit duplicity, misinformation, and good-cop-bad-cop poses to tease information from their captives, but they viewed physical violence or torture as unacceptable. And their techniques, often unorthodox, paid off handsomely in actionable intelligence used by commands across the European theater.

All had been victims of disruption and displacement, but each evolved as a distinct personality. Of the six, perhaps Selling maintained the strictest decorum during interrogations, remembering his prewar days in Dachau and how he wished he had been treated by his captors. Steinfeld, serious from childhood, acted as a translator for a surrender agreement between American and German generals after Hitler’s death. Lewy, sent to an orphanage when a youngster and almost killed when Nazis locked him and other boys in a synagogue and pumped in gas, always pushed the interrogation envelope, once ordering a German officer to dig his own grave and lie in it until he talked.

Stern, who moved in with his baker uncle in St. Louis and scored an interview with novelist Thomas Mann for his high school paper, brashly put himself forward when Marlene Dietrich arrived for a USO show and personally acted as her guide during an inspection of a POW camp. Brombert, remembering his romantic prewar Paris days, appropriated a Jeep without permission and raced to the City of Lights after its liberation, where he discovered that new delights awaited. But he also found time to participate in the Normandy, Saint-Lo, and Hurtgen Forest offensives. And Angress, who parachuted into Normandy with the 82nd Airborne without even a practice jump, was the only one among the six who was captured. He was liberated after a few weeks and extracted useful information from the German who had guarded him.

The missions of the Ritchie Boys involved enormous and disproportionate odds. They would rove as quasi-independent entities within larger units, and their capture would almost certainly mean death. It was common for them to change the “H” (for Hebrew) on their dog tags to “P” (for Protestant) for just such contingencies. Another risk factor came from their own side, when GIs turned trigger-happy after German soldiers appropriated the clothing and equipment of dead Americans and began impersonating them during the final, desperate phases of the European conflict. No matter how idiomatic their English had become, the Ritchie boys’ voices still bore traces of an accent.

Theirs are narratives of family ties, love of new country while feeling the tug of the old, Jewish values rather than religiosity, and, most importantly, the indomitability of the human spirit. Fittingly, Henderson closes the circle on their turbulent early chapters by adding postscripts about their lives in America after the war. All furthered their educations, with several going on to teach at the college level; one became a manufacturer; and another an accountant. And Angress also was the only one of the six to return to live in Germany post-retirement, so he could speak to young audiences in their native tongue and remind them what their parents and grandparents inflicted, and what difference-makers they could become.

Jonathan E. Lazarus, a former editor of the Star-Ledger, is a proofreader at the Jewish Standard.