Would the Second World War have ended the same way if Hitler's Germany had developed an atomic bomb? At one point, the Nazis were tied with the Allies, even after driving away many gifted brains by their racial policies, but lost the race. A crucial reason was denial of a vital ingredient in a campaign by those fully conscious that their activities meant trouble for their families and other citizens.

How this happened is a tale that seems laughably unbelievable. A team of highly-trained, heavily-armed commandos make their way into a well-guarded industrial complex in Nazi-occupied Norway, blow it up and escape without even the German guards knowing anyone was there, leave alone firing a single shot.

But this episode, likely to be known to war movie buffs who have seen "The Heroes of Telemark" (1965), was only part of an operation which was much longer, more complicated and definitely stranger than the Kirk Douglas-Richard Harris starrer.

Telling the full story, in all its improbable highs and tragic lows, is American journalist and author Neal Bascomb in his latest book.

Known for his works, including the attempts to break the four-minute mile by a trio of Oxford students, the mutiny on the Battleship Potemkin, and the long search for Nazi war criminal Adolf Eichman, he begins with the story of a French attempt in 1940 to source a large consignment of heavy water from its manufacturer, Norsk Hydro in then neutral Norway.

In true thriller style, it follows the French agent's nail-biting attempts to get these stocks home under the nose of Germans, before giving a sketch of the German takeover of Norway and their dismay at finding out that the Norwegians did not live up to their idea of a fellow Aryan people, and created great trouble with a spirited resistance movement.

It is here that Bascomb introduces us to the varied crew of Norwegians who fled across the North Sea to Britain to take part in the greater struggle or those who abandoned their usual lives to pick up arms at home, both combining to eventually accomplish perhaps the greatest strategic victory for the Allies — the destruction of a heavy water plant whose output was desperately needed by the Nazis.

In the stories of Leif Tronstad, the physics professor who fled to Britain and became a key planner for clandestine operations though always wanting to return home to fight, of Martin Linge, of Knut Haukelid, Einar Skinnarland, and many others, he presents a tale of devoted patriots that should serve as a model even now.

Intertwined with this is the equally riveting account of efforts on ways to gain control of the immense power in the atoms by mastering nuclear fission on both the Allied and the Axis sides, and the former's attempts to subvert their opponent's efforts.

It thus has all the makings of a first-class thriller but Bascomb strives to make it as real as possible. You may find that there is a lot of detail about training, planning and preparation, while the actual action seems much shorter in comparison — but then that is how it happens in real life.

There is plenty of tragedy — Tronstad's own case, the fate of the Royal Engineers sent to sabotage the plant, and finally the necessity of blowing up a ferry on which the Nazis are transporting the last of the heavy water, while knowing that many civilian passengers will also be killed.

And there are plenty of dramatic incidents — nerve-wracking climbs of steep cliffs with heavy loads in the dark, fleeing pursuing German soldiers on skis and turning back to shoot the closest pursuer, hiding from your own father to prevent him from knowing you are back, explaining the pistol that fell from your pocket in a hotel full of German soldiers and more.

But the real value is showing how these Norwegians (many who went on to live long lives while one is still alive) operated while knowing that their task meant at least long separations from their families, trouble for their relatives and their associates from the vengeful and vicious Nazis, and deaths of many innocent compatriots — but accepted all these as necessary sacrifices.

This is true patriotism — not peddling hate speech on social media.

Title: The Winter Fortress; Author: Neal Bascomb; Publisher: Head of Zeus; Pages: 399; Price: Rs 499