Winston Churchill called World War II's Battle of the Bulge "the greatest American battle of the war." Steven Spielberg engraved the 6-week ordeal on the popular imagination with Band of Brothers, which dramatized the attack on the village of Foy by three companies of the 101st Airborne Division, the Screaming Eagles.

Now, British military historian Peter Caddick-Adams is drawing on his years spent reconstructing the epic battle in his just-published book, Snow and Steel: Battle of the Bulge 1944-45. Speaking from a British military base in Germany, he talks about Hitler's reasons for launching the offensive, why crystal meth was the drug of choice for the Wehrmacht, and what lessons the battle can teach us today.

How did the battle get its name? What was the Bulge?

To begin with, soldiers weren't sure what to call the battle. It was a German penetration into the American lines, which the Americans had then surrounded and eventually sealed off. The word for that in the First World War was "salient." But that sounded too formal, perhaps too British. An American journalist was interviewing George Patton. The journalist needed a unique, American-sounding word that could become shorthand for the battle. And the word "bulge" popped into his mind. It was adopted pretty soon after the battle, and it stuck.

View Images Peter Caddick-Adams traces his interest in the Battle of the Bulge to a trip he made to the Ardennes as a teenager in the mid-1970s. It made "a huge impression," he says. Photograph courtesy of Random House

Your interest in the battle began with a schoolboy epiphany. Take us back in time.

I had some friends who restored secondhand military vehicles. One summer in the mid-1970s they invited me to return to the area where the Battle of the Bulge had been fought. We drove in these vehicles, and to make it look right, we put on some khaki, then drove through the little villages of the Ardennes.

I was amazed by the older generation, who came out of their houses and could remember what was by then 30 or so years earlier. You could see by their faces how much it had meant to them. Some of them burst into tears the moment they saw a U.S. jeep.

One farmer led us up a small trail to the top of a hill and showed us where the American and German lines had been. I couldn't see anything, which was somewhat of a disappointment. Then I kicked idly at a stone. It turned out not to be a stone but an entrenching tool. All of a sudden beneath the undergrowth, when I looked, there were cartridges, bits of helmet, canteens—all the debris you'd associate with a battle. When you're a teenager, that makes a huge impression.

You say Hitler's decision to launch the Ardennes offensive was more political than military. How so?

I feel I was breaking new ground by asserting that the decision by Hitler to launch the Ardennes attack—and it's his alone—is a political one rather than a military one. The traditional view is that this is an attempt to turn around the military situation as it was at the end of 1944. (See a World War II time line.)

I came to the conclusion that this is rather Hitler's attempt to reassert his personal political control over the German general staff and the entire Nazi hierarchy. It's a reaction to the von Stauffenberg bomb attempt on his life on the 20th of July, 1944. After that, he hides away. He goes into shock. He doesn't know whom to trust. His health goes downhill. The genesis of Hitler's plans to launch the Bulge is his grappling to retain control of the direction of military affairs and prove to the Third Reich that he's still the man at the top.

A fascinating section in your book explains the mythological and cultural significance of forests to the German psyche. How did the Ardennes campaign fit into this?

Again, I think I was breaking new ground here. I wondered why Hitler had specifically chosen the Ardennes. It's his plan, and everything about it had to have significance. Therefore, I wondered if there was more to the Ardennes than simply a region where the Allies were weak. I went back to Hitler's pronouncements, his beliefs, and his fascination with Wagner. In Wagner, a huge amount of the action takes place in woods and forests. This taps into the old Nordic beliefs and gods—that woods are a place of testing for human beings.

If you look at the whole Nazi creed, the false religion that Hitler and the SS created, woods and forests crop up time after time. Even the code name for the offensive, Herbstnebel—Autumn Mist—has all sorts of Wagnerian connotations. Wagner uses mist or smoke to announce the arrival of evil. So it was no accident that the attack against the Americans was launched from large forests, in heavy fog.

View Images U.S. infantrymen with General George Patton's Third Army advance at dawn on German gun positions to relieve encircled airborne troops at Bastogne on January 7, 1945. Photograph by Bettmann, Corbis

Hitler had a very low opinion of the Americans as a fighting force. Why?

Hitler thought the Americans were a mongrel force made up of all sorts of different nations. But that's a blatant misreading of history. For a start, Germany itself is a mixture of all sorts of different nations. Huge numbers of Americans who went to fight in the Ardennes in 1944 had also come originally from Germany. He also overlooks that so many great American figures were originally German. Eisenhower originally came from the Saarland. Pershing, the American general in World War I, is a German name.

All Hitler's knowledge of the United States is from reading cowboy books written by a charlatan writer called Karl May, who'd never actually been to the United States. So Hitler is remarkably ill-equipped to make these sweeping generalizations about the Americans—particularly about their ability to mass manufacture, which is one of the things that bring about his downfall. The Germans are going into battle barely better equipped than they were in 1914, with upwards of 50,000 horses. By contrast, the Americans are fully mechanized.

A figure who strides out of the pages of the book is the cigar-chomping American general, Patton. In what ways did he typify the American character—and fighting tactics?

It's difficult to discuss the Bulge without referring to George Patton, with his cigars and trademark pearl-handled revolvers. He is so American, from a British point of view. What do I mean by that?

Well, he had unbounded confidence. And, I think, one thing that marks out successful captains in history is a superb confidence that almost borders on arrogance. That's something Patton has. He would always say that a perfect plan is not as good as an imperfect plan that's executed violently and immediately.

One of the key aspects of the battle is the speed with which he can reorientate his Third Army, which is to the south of the Bulge, and get them to counterattack the Germans by moving north. To turn a whole army around on its axis by 90 degrees and move north in the middle of winter at almost no notice is almost unheard of.

But Patton achieves this within a couple of days—much to the amazement of the Germans and even more to the amazement of his fellow Allies. He says he will do it. Most people don't believe he can. Yet, my goodness me, he delivers, and delivers in spades.

View Images Patton was one of the most aggressive and able generals of World War II. He projected "a superb confidence that almost borders on arrogance," author Caddick-Smith says. Photograph by Corbis

On the other side, one of the most compelling characters is the German Panzer commander, Joachim Peiper. He was nasty bit of work, wasn't he?

Joachim Peiper was a 28-year-old true believer in the Nazi faith. His whole life had been acted out in the shadow of Hitler and the Third Reich. He'd come to prominence early. He was a colonel in the Waffen SS and worked as an adjutant to Himmler. He was involved in a whole series of war crimes on the eastern front, where he taught his men to regard Russian lives as being worth nothing.

He and his men bring this mentality to the western front when they fight in the Bulge in 1944, and it's they who perpetrate the famous massacre just outside the town of Malmedy.

I also wanted to try and strip the gloss off Joachim Peiper as a brilliant military commander. One of the points I make in the book is that he had passed his best in a military sense. His performance wasn't nearly as good as he claimed it to be. When I went back through the records, I found he'd lied about the progress he'd made during the Battle of the Bulge.

One of the things that most surprised me was your contention that the use of crystal meth was widespread in the German army.

The Germans routinely encouraged their soldiers to take what we would now call crystal meth before battle. It would whip them up into a fury and may explain some of the excesses they committed. It's a way of motivating scared young men. And some of the Germans are very young indeed. I found lots of evidence of 16-year-olds being put into uniform and sent into battle.

So I think you're reaching for every possible technique to exaggerate your soldiers' combat performance. This wasn't just an SS thing. The German army was not below stooping to use drugs to increase its soldiers' effectiveness on the battlefield.

What are the most important lessons, militarily and personally, you took away from studying the battle?

Writing military history is fascinating because you never end up where you think you will. One of the things I took away was how much the Allies deluded themselves as to the situation of their opponents—how much they believed, because they wanted to believe, that the Germans were a spent force. The Battle of the Bulge proved exactly the opposite. And we do this time and time again. We under-appreciate the effectiveness of our opponents even today.

Personally speaking, I was fascinated and humbled by the resilience of the soldiers, particularly the Americans, I met, whether personally or through their letters and diaries. I have seen action in combat zones myself. But I could have no conception of the horrific, freezing conditions that the American soldiers coped with and overcame.

What I took away is that soldiering is not about planning. It's all about how you react when something goes wrong, when the wheel comes off—how quickly you can turn things around, how resilient and deep your resolve is. That was demonstrated in spades by the U.S. Army at the Bulge. And that is deeply humbling and very instructive.

How many Bulge veterans are alive today?

There are precious few. Of the several hundred thousand that took part in the Battle of the Bulge, only a couple of thousand are now left with us. Most of those are fading fast, which is one of the reasons I wanted to write the book for the 70th anniversary. I knew that if I left it any longer, there'd be no one left around to say, "Yes, that's how it was," or "No, the author's talking a load of rubbish." [Laughs] I wanted to write it as a tribute to those who'd fought in the campaign, while there were still some of them left alive to appreciate my comments.

Simon Worrall curates Book Talk. Follow him on Twitter or at simonworrallauthor.com.