“Alone” (Liveright Publishing Co.), by Michael Korda

Interest in the 1940 cross-channel evacuation of British soldiers amid the French collapse in World War II has sprung to life this summer, thanks to Christopher Nolan’s blockbuster movie “Dunkirk.” On its heels comes “Alone,” Michael Korda’s masterful account of that epic drama and its impact on his family.

Few of the soldiers, airmen and mariners whose heroism allowed Britain to carry on a singlehanded battle against Nazi Germany are alive today. Korda was only 6 years old at the time, living in London with his filmmaking family whose roots were in central Europe. But he was remarkably aware of events that propelled Europe into war.

Korda recounts how he and his family had to cut short their August vacation in France as war clouds thickened in the weeks prior to Adolf Hitler’s invasion of Poland. They were glued to the radio for Neville Chamberlain’s grim announcement that Britain was at war. The author recalls air raid sirens, the family’s temporary move to the countryside and his evacuation to a farm in Yorkshire followed by his stay at a boarding school on the Isle of Wight before his return to London.

Korda’s family was moviemaking royalty. His uncle, Alexander, was a renowned producer and director, married to actress Merle Oberon, and his father, Vincent, was a film art director. When war broke out, the family production company, London Films, was in the midst of one of its most ambitious projects, the Arabian fantasy movie “The Thief of Bagdad.”

“Alone” describes in detail the tense political drama that surrounded the emergence of Winston Churchill as prime minister just hours before Germany invaded France and the Low Countries. Alex was a longtime friend and supporter of Churchill, who gave his blessing to the producer’s decision to move his operation to Hollywood after wartime manpower demands made it impossible to finish his films in England.

The trans-Atlantic move had the British government’s clandestine blessing and financial support in hopes that Alex’s subsequent film “That Hamilton Woman,” about Admiral Horatio Nelson and his mistress, would build pro-British sentiment in the United States.

Family issues highlight some of the more fascinating dynamics in “Alone,” but the book is first and foremost a riveting account of the fate of the 300,000-man British Expeditionary Force during its retreat toward the English Channel as German tanks overran Belgium and set their sights on Paris in a blitzkrieg that left France demoralized and prey to a wave of defeatism and recriminations.

Illuminating profiles of key players include those of Vice Admiral Bertram Ramsay, architect of the evacuation plan dubbed Operation Dynamo; German tank warfare strategist Heinz Guderian; and a string of hapless French generals. On the political side, we meet the British appeasers whose lapses in judgment paved the way for Churchill — described by Korda as “that rarest of men, a well-functioning, even hyper-functioning alcoholic” — to rally his people to ultimate victory.

Perhaps the biggest question that Korda and other historians have struggled to address is why the Germans temporarily halted their race to the channel, a decision that allowed Britain to assemble a fleet that ranged from Royal Navy destroyers and commercial ferries to fishing boats and yachts, enabling its troops to survive and fight another day.

Some suggest that Hitler chose to spare the British army as a sign of his good intentions and encourage a peace settlement. For his part, Korda believes the three-day rest break was designed to prepare the panzer divisions for the decisive encounter with the French army while delaying an advance in the marshy terrain of Flanders.

“Alone” reaches its climax in the days depicted in Nolan’s film. The author’s descriptions of fire and smoke along with smells of burning rubber and unburied bodies evoke images as vivid as any to hit the screen. One writer quoted by Korda likens it to “a scene from Dante’s Inferno.”

Korda likens the evacuation to a big lottery. “Some people went to the beach, fell into the right line, were taken aboard a ship with a minimum of drama, and disembarked a few hours later at Dover.” Others were shelled while on the beach, machine-gunned by German aircraft or drowned when their ship was mined, bombed or torpedoed.

A total of 338,226 troops, including 139,921 French, made it to England, but it was only months later — after the Battle of Britain — that fears of invasion dissipated and the “spirit of Dunkirk” became cause for celebration. It was, according to Korda, “that rarest of historical events, a military defeat with a happy ending.”

It is rare and fortuitous that this spellbinding account came out within weeks of the release of Nolan’s film that struck box-office gold. One can only hope that many of those drawn to the movie will go on to read “Alone” to delve further into the details and context of that historic episode.