I met an author the other year who had written a successful book about a famous battle in U.S. history. In the course of talking about the book, he mentioned that he had never visited the ground, and I was surprised. No, I was shocked, and it changed the way I approach my own writing because, as I thought then and continue to think, how can a writer recount a true story without intimate knowledge of the setting?

Potosi was unlike any mountain I had encountered in the past. Only through the climb could I get to know it as a character in Fireball.

I climbed Mt. Potosi in part because of this guy and our chat. I knew Potosi was going to be more than terrain on which my cast struggled; Potosi was in itself a character in Fireball and in opposition—Man against Nature—with my heroes. In the past I’ve climbed in mountains, but they were lush eastern mountains, and I’d had no experience with desert mountains with cactus and Joshua trees. So, if I had never climbed Potosi, my inclination would have been to write eastern mountains and not desert mountains. And because I climbed to the site of the crash of Flight 3 over the first-responder route, I could speak of that particular experience up the dry wash and scrambling between the cliffs, then over rises and into hollows and then up into the final ravine. I could speak of every lethal danger because I saw and experienced them.

You’d think judging by this 1930s photo of the Café Trocadero on the Sunset Strip that these were flat lands. But the Troc was built into a hillside, with a sheer drop behind it–something you would only know from being there.

How can you write a book about Hollywood and its stars without visiting the place and learning that “Hollywood” doesn’t mean a city with defined boundaries? Hollywood is a chunk of Los Angeles, and Beverly Hills, and Century City, and extends toward Culver City and the ocean. Hollywood is ultra-green, overwatered lawns in a desert. It’s volcanic mountains jutting up out of nowhere and houses built into the mountains accessed by goat paths that no one ought to drive over. Hollywood pulses to the beat of its major arteries, Hollywood Boulevard, Sunset Boulevard, Santa Monica Boulevard, which take you, block by block, from silent-era art deco to billion-dollar office buildings in gleaming gold, and from crumbling adobe apartments full of struggling actors to sprawling mansions of those lucky enough and talented enough to score big in show business. How could you write about the Sunset Strip of the 1930s without walking along that little piece of real estate with Ciro’s on one side of the street and Mocambo and Trocadero on the other? How could you even imagine how quaint it is? How confined and built on ledges? How packed in the stars were when they hit the town? Everybody had to know everybody just because of the terrain of the land they call Hollywood.

Now I’m heading into my next book about the Eighth Air Force in World War II, and my first inclination was to fly in the big bombers that conquered Germany in 1944 and 1945, so I booked myself into the cockpit of one of 10 remaining airworthy B-17s and went up. Up a grand total of 1,500 feet, but up nonetheless, and experienced something of what the boys of the Greatest Generation did in the airship known as the Flying Fortress. Now, I have a sense of the roar of four big Pratt & Whitney engines, of the confines of the cockpit, of the catwalk over the bomb bay, of the treacherous footing skittering around the lower turret, of the size of the bombs, and of feel of the waist machine guns. I know what it feels like to crawl into the nose of the plane in flight and where the bomb sight was and where the bombardier and navigator sat and what they could see out the observatory-style nose. Up those 1,500 feet I could begin to experience the terror of being a target for guns on the ground, knowing that a strike on the wing or the tail section meant sure death or bailing out at 10 or 20 times my 1,500 feet. I realized for the first time just how unpressurized the cabin was, and it hit me how vulnerable were the airmen, on oxygen at 30,000 feet with the temperature 30 below and anti-aircraft guns booming from the ground, and German fighters buzzing around rattling the ship with machine gun fire. Do you have any idea how big and heavy a .50 caliber machine gun shell is? I do, now, after holding one in my hand. It looks more like a small bomb than a bullet, and the machine gunners fired them in belts nine yards long. Hence the term, “the whole nine yards.” What’s the physics of firing shells that size out of both sides of a plane flying at 300 miles per hour, and out the tail and above and below? I couldn’t tell you, but after being aboard a B-17, now at least I know enough to ask.

There’s always another mountain to climb. I’ve got to find a B-24 and fly in it. I’ve got to go to where the bombers departed in England. I might have to go see where the bombs fell in Germany—who knows? It’s all part of telling authentic stories where the characters aren’t just people. Sometimes, they’re mountains, or airplanes.

Flying in a B-17 is research just like digging through federal records. This B-17 was built in 1945 and used in filming of the 1990 feature, Memphis Belle.