I started with the book ...

I started with the book Boardwalk Empire and then immersed myself in the history of Atlantic City, World War I, the temperance movement, Prohibition, pop culture. I even read the news and magazines of the period just to soak in it. That was before I even started thinking of the story.
 Terence Winter

Quotes from the same author

I'm always amazed by writers who say, "Oh you know I had a half hour so I sat down and wrote a little bit." I just need a real big chunk of time to sit down and focus. That's my process.
 Terence Winter