As a reporter for The Washington Post, Wil Haygood has written about a range of topics: a historic church moving after 52 years; victims of the Rhode Island nightclub fire; the mother of slain gay college student Matthew Shepard. But perhaps none is as complex as the subject of his new book, legendary song and dance man Sammy Davis Jr.

Virtually abandoned by his mother at birth and raised on the road by vaudevillians, Davis was a fascinating figure who, in the 1950s and ’60s, brazenly did things that black men weren’t supposed to do: convert to Judaism, court white women, become successful. In the biography “In Black and White: The Life of Sammy Davis Jr.,” to be published by Knopf in October, Haygood tells Davis’ sobering and singular story with probing insight and a poetic touch.

We caught up with Haygood by phone to get his take on writing biographies and why we should still care about Davis.

Q: Describe the moment when you decided to write the book.

A: When I finished my last book, a memoir that came out in 1997 about my own family (“The Haygoods of Columbus: A Love Story”), I started thinking that it would be nice to get back to a big subject, a person’s life. Actually, [I had to decide] between doing a book on Sammy or Nelson Rockefeller. But in the end it seemed that it would be more enjoyable to sit in a room and study at night with Sammy as opposed to Nelson Rockefeller.

And when I started talking to friends — my white friends, to be totally honest — they thought it was a wonderful idea, and they relayed stories to me about having heard their mothers and fathers tell stories about seeing Sammy out in Las Vegas, or Reno, or L.A. And that was exciting to hear. But my black friends, with some exceptions, thought that Sammy’s life was a waste. I think a lot of our memories were of Sammy with [Richard] Nixon, Sammy and Frank Sinatra, and Sammy and the racial jokes with the Rat Pack. So, right then, I knew I had a rub, black and white. And it was right there when I knew that I would write the book.

Q: Why do so many black people have a negative impression of Sammy?

A: It’s sometimes extremely painful to look at what Sammy Davis Jr. had to go through to get to where he arrived at. He was always searching for who he really was. We also saw him in an interracial marriage in the 1960s. That was when black folk were trying to say to the world, “Black is beautiful,” and here’s Sammy Davis Jr. going down the other side of the road. It really affected people’s view of him.

Q: You’ve also written a biography of civil rights leader Adam Clayton Powell Jr. What draws you to biography?

A: Well, I don’t write novels. I don’t have that muscle. And there’s just a stream of lives out there that I would like to write about. In each of these books — Powell and Davis — I went into them wanting to be exhausted at the end of the journey. I wanted to be made to feel tired. I wanted to know that I worked as hard as I could, and that these individuals had truly tested me.

Q: One of the tests of the Davis book surely must’ve been when you took his mother to the theater. Can you describe that incident?

A: I didn’t know at the time that his mother was still living, and I tracked her down. She was very tight-lipped and didn’t have a lot to say about Sammy being out on the road when he was young and her not putting forth a lot of energy to find him. The interview ended and I was sad. I got to the door of the apartment where she was living in New York and I asked if I could see her again. She said, “Well, I don’t ever have a chance to get out.” And I said, “What if I come back and take you out?” I asked where she would like to go and she said to see a play. I suggested “Ragtime.”

I came back a couple of weeks later, and there we were in the lobby. She was dressed beautifully. We went to the elevator to go downstairs and it was broken. She started screaming at me and told me that I should’ve called ahead and checked that. It was an amazing moment, because it truly explained why all the other people I had interviewed thought she was a tough lady with streaks of meanness. And that she was. She made it clear that she was unhappy that the elevator didn’t work and she blamed me for it. It was chilling. But I will say this: She would call me sometimes after that and just say, “How are you doing? How’s your mother? Have you called your mother today?”

So there were these very tender moments that I saw with her. There’s a line late in the book where I say, “Sammy would always wonder if his mother truly loved him. Who knows? Who are we to ask?”