Amanda Vaill says she figured her new book Hotel Florida: Truth, Love, and Death in the Spanish Civil War would be a relatively easy project by comparison (her previous book, Somewhere: The Life of Jerome Robbins, took seven years to research and write).

“I said, ‘I know what I’m going to do next. I’ll do something where there are no grandparents, no childhood, no mid-career dissolution. I’m going to make it really short: I’ll drill deep into a short period of history…it will be finite.’ Then I ended up doing this book which turned out to be so much more complex.”

Set against the highly eventful backdrop of the civil war-torn Spain of the 1930s, the extensively researched Hotel Florida weaves together history and biography, illuminating the interwoven wartime fates of three larger-than-life couples. Readers encounter a vulnerable Ernest Hemingway and his young, ambitious lover Martha Gellhorn; Robert Capa and Gerda Taro, Paris-based photographers who intend to capture history and invent photojournalism; and the press officers Arturo Barea and Ilsa Kulcsar (who, in covering the Spanish Civil War, would come to understand Hemingway’s words, “It is very dangerous to write the truth in war, and the truth is very dangerous to come by”).

As researcher, Vaill wants to know everything she possibly can about her subjects. “Just hearing about them from the outside is not as interesting. I always want to get to the archives, the family, to be as close as possible,” she says. “I do all or most of the research first, because I don’t know what I’m going to write until I have the bits and pieces.” That’s why she never uses a research assistant: “I have no idea what I want until I get it! But I will know it when I see it. I know where I want to look, but not what I will find.”

Vaill makes archival research sound like a treasure hunt, one that has her breathlessly combing through unpublished letters and diaries, documents and reels of film. “You have no idea what you’ll find. And sometimes it’s nothing, other times riches you would not believe. Boxes of old letters or journals come forth from document storage places. You open them and suddenly you’re surrounded by the smell of old paper and old typewriters.” Then, she says, her job is to listen intently. “It’s…almost as if each document has a voice of its own. Like you’re listening to a radio broadcast of another era. Tuning in to this other world.”

Her ability to breathe life into history is tied to this act of listening, “this sense of a voice telling a story.” Vaill acknowledges that sometimes she finds herself exasperated by the people whose story she is telling. “I can be mad at them, or furious at what they’re doing. Sometimes they’re so self destructive!” But inevitably she comes to understand the people she is writing about more fully, in the context of their historical moment, which in turn helps her create the complex and ultimately sympathetic portraits for which she is widely praised.

After forming such close relationships with these characters over time (she still marvels that she was able to complete this manuscript in just four years), Vaill says finishing the project was a bittersweet moment—and something she postponed a little. “When I finished the book, I told my editor, ‘Now I have to write an epilogue.’ And he said, ‘You don’t have to.’ And I said, ‘Yes, I have to write one.’ ” In a way, writing that epilogue let her lay to rest those vivid voices she had brought back to the world of the living.

“I had to say goodbye to them. And that’s how I did it.”

Jessie C. Grearson is a freelance writer and writing teacher living in Falmouth, Maine. She is a graduate of The Iowa Writers’ Workshop.