Sampling champagnes and sniffing perfumes may seem like pastimes of the idle rich, but for luxe historian Tilar J. Mazzeo, it’s all in the name of research. The bestselling author of “The Widow Clicquot” releases her second biography of an icon this month. “The Secret of Chanel No. 5” ($26, Harper) reveals closely-kept secrets, marketing blunders and serendipitous events that made No. 5 the bestselling perfume in the world.

Why write a biography about Chanel No. 5?
There’s a fabulous story of the woman, but there’s a really interesting story behind the perfume itself. I wanted it to be a great beach or train read about a product that is one of the most famous luxury icons in history. It’s also about a successful entrepreneur.

Why is it so mythical?
I did a lot of research on perfume for the book, and every perfumer I’ve talked to agrees, even competitors: Chanel No. 5 is a masterpiece of composition. Part of it is that it’s really a great perfume. One of the five great perfumes of 20th century.

Did her celebrity affect the perfume’s success?
She had very little to do with the business after 1924. The decision to sell it through the U.S. Army during the Second World War changed it. In that moment of deprivation and cultural trauma for Europe and America, Chanel No. 5 becomes a symbol of a better time. It was transformed into an icon at that moment.

Coco Chanel is often depicted as a cunning, complicated woman. How do you view her?
When you write a biography, you either fall in love with the person or you don’t. I would have to say, truthfully, I am a bit distressed by her opportunism at moments. She is clearly a brilliant designer and savvy, cunning entrepreneur, but there were moments when she was a very hard woman.

Why is she idolized?
For the modern woman, she’s part of what liberated women’s fashion. Until the 1930s, women wearing trousers were considered scandalous. Chanel targeted a sexy, feminine and liberated woman who could wear a jersey dress and fake pearls and trousers and be feminine. That resonates still.

You write about the allergen controversy surrounding perfume. Should perfumes and oils be regulated?
No, the reality is if you’re sensitive to natural jasmine, there’s an easy solution: Don’t spray perfume on your skin. Spray it on your clothing. We’re talking about regulating natural rose oil and natural jasmine oil. If you’re that sensitive, maybe you just don’t want to wear perfume at all.

Why is understanding luxury important for culture?
We buy luxury products because they allow us to tell a story not about who we are but about who we want to be. At their most basic level, they’re aspirational. But they’re also a way of dreaming out loud to each other.

Next book?
I just started a new one entitled “The Ritz at War.” It’s on the history of the Ritz Hotel in Paris during the [German] Occupation.

What is your scent?
Chanel No. 5 Eau Premiere. I wear the updated lighter version and the Eau Premiere boutique line.