Whenever I finish a book, I start with a blank slate and never have ideas lined up.

As a rule, I am very skeptical of tying books to anniversaries. I don't think readers care. I also feel that it just about guarantees that somebody else will be writing a book on the same subject, but being a former journalist, I'm always interested in, like, why write about something today? Why do it now?

It's essentially taught in high school and college survey courses as an item on a timeline: 'The Lusitania was sunk; the U.S. gets into World War I'.

I'm often associated with parallel narratives or dual narratives. The 'Devil in the White City' was a fluke.

I knew from an online search that the Wisconsin State Historical Society, on the vast University of Wisconsin campus, held the papers of Sigrid Schultz, a spunky correspondent for the 'Chicago Tribune' who became one of Martha Dodd's friends in Berlin.

I knew Berlin would have to become a kind of character in my new book, 'In the Garden of Beasts'. I had felt likewise about Chicago when I wrote 'The Devil in the White City' and Galveston with 'Isaac's Storm'.

We, of course, have the power of hindsight in our arsenal, but people living in Berlin in that era didn't. What would that have been like as this darkness fell over Germany?

After I finish writing a chapter, I'll print it out, cut it up into paragraphs, and cut away any transition sentences. Then I shuffle all the paragraphs and lay them out as they come. As I arrange and hold them next to each other, very quickly a natural structure for the chapter presents itself.

One of the really amazing things about the Lusitania saga was that, at the time, there existed in the admiralty a super-secret spy entity known as 'Room 40'.

It's not my intent to write definitive history. 'Dead Wake' isn't a definitive history of the sinking of the Lusitania. It's my account.

President Hindenburg had ultimate say over whether the government would survive or not.

'The Devil in the White City' - the 'White City' was the nickname for the World's Fair of 1893, the World's Columbian Exposition in Chicago.

I found a book facing out that I'd always meant to read: William Shirer's 'The Rise and Fall of the Third Reich.' About a third of the way through, I suddenly, finally caught up to the fact that Shirer had been there in Berlin, from 1934 on, and was finally kicked out when the U.S. entered the war.

There's a powerful appeal in the 'I didn't know that' effect. I love it when people say, 'Gosh, I didn't know that.'

When I'm considering an idea, and there is an element of hubris involved, I generally feel comfortable that it's going to be a good story. Pride goeth before a fall. It's an element of a lot of big stories.

I do think hubris played a role here as well, the belief that the Lusitania was too big and too fast to ever be caught by any submarine, and that, in any case, no U-boat commander would think to attack the ship because to do so would violate the long-held rules governing naval warfare against merchant shipping.

When I'm in New York, I have, like probably everybody else in Manhattan, a white-noise generator to use at night: a Marpac Dual-Speed Dohm-DS. It is terrific. I've never slept better in the city.

As a writer, you always try to imagine, 'What if I were in a situation like this? How would I react?'

As my friends will tell you, I am a superior agonizer. Believe me, you do not want me in the cockpit of an airliner. But in my defense, choosing an idea is also a high-stakes affair.

I was in Bucks County at the 'Bucks County Currier Times,' which is a great place to start for any reporter who wants to start out.

There is something about the name Berlin that evokes an image of men in hats and long coats standing under streetlamps on rainy nights.

It was a civilian ship, and the Lusitania could outrun any submarine. So this population of people was very confident that Cunard and the Royal Navy would be looking after them. Why weren't they under convoy? That's the real question.

It was David McCullough's 'The Johnstown Flood' that lit my imagination as to how I might one day go about writing book-length nonfiction, though my favorite of his books is 'Mornings on Horseback,' about the young Teddy Roosevelt.

I figured, correctly, that Berlin in February was not a destination coveted by tourists. I found good airfares on Lufthansa, an airline I quite like, and got a great rate at a brand new Ritz-Carlton, which clearly hoped to seduce visitors into forsaking Hawaii for Potsdammer Platz.

I thought I'd go to a bookstore and see what moved me.

One of the things I've always loved is collecting telling little details.

What is clear is that in 1900, Galveston was growing fast, had already become the number one cotton port on the Gulf Coast, and was already being referred to as 'the New York of the Gulf.'

The toilet from time to time imparted to the boat the scent of a cholera hospital and could be flushed only when the U-boat was on the surface or at shallow depths, lest the undersea pressure blow material back into the vessel.

I think, one day, I might actually try writing a bunch of - a collection of essays maybe on the funnier side of the spectrum. I don't know. But it's fun to have, frankly, Twitter as kind of an outlet. When you're writing about dark things all day, it's kind of fun to have fun.

Hitler was such an anomalous character - he was so over-the-top chaotic in his approach to statesmanship, his manner and in the violence which overwhelmed the country initially. I think diplomats around the world... felt like something like that simply would not be tolerated by the people of Germany.

The head of the hurricane research division, Hugh Willoughby, told me that hurricanologists can predict the behavior of storms if those storms behave predictably.