First sentence: It was Edwin who wanted to build a new house.

Love affairs, architecture, fame, feminism, scandal, arson, murder, despair. The true-life story of the ill-fated love between Mamah Borthwick Cheney and famed architect Frank Lloyd Wright is so rich with sexy topics it’s hard to believe it’s barely more than a footnote in most Wright biographies.

It’s even harder to believe it took so long for a writer to mine the story for a novel, but Nancy Horan does it beautifully in her debut work, ”Loving Frank.”

The book took seven years to research and write, and Horan’s meticulous fact-finding and storytelling was rewarded with a spot on the New York Times Bestseller list and an interest from book clubs when it was only out in hardcover. With the release of the paperback today, it will likely become the next book club favorite.

While much is known about Frank Lloyd Wright — his genius, his flamboyance and his ego — Horan chooses to tell the story through the perspective of Mamah Cheney, an intelligent, well-educated woman who embraced feminism and was not content to idly watch her life float by in the genteel Chicago suburb of Oak Park in the early 1900s.

This we know is true: Mamah (pronounced MAY-muh) and Edwin Cheney commissioned a house from Wright. As it was being constructed, Mamah and Wright fell in love. They each abandoned their families — he with six children and she with two — and lived together in Europe for awhile. Edwin Cheney divorced Mamah, but Wright’s wife, Catherine, refused to believe it was more than a fleeting affair and would not grant a divorce. When they returned to the states, they set up house on the Wright family land near Spring Green in Wisconsin. Here is where Wright would build the famous Taliesin for Mamah, and where she would die a few years later at the hands of a crazed, disgruntled worker, who set fire to Taliesin and axed those trying to escape.

Horan, a journalist, uses newspaper accounts, biographies on Wright, and Wright’s own writings to fill in the gaps of the story. But her greatest find was a collection of 10 letters written by Mamah to the Swedish feminist Ellen Key, whose work Mamah translated into English for publication in America. While only a portion of one letter appears in the book, Horan uses the letters to help shape Mamah’s personality and flesh out a three-dimensional woman who struggles between being true to her feelings for Wright and honoring her commitment to her husband and children, while at the same time finding her own path to independence from either of those influences.

The lines between fact and fiction are expertly blurred in the book, and at times you wonder if the diary entries you’re reading are really Mamah’s (they are not), or if the newspaper accounts that vilify Mamah are actual excerpts (they are). The dialogue Horan imagines between the two lovers is believable, although totally fabricated, as they share ideas on art, literature, architecture, nature, love and other subjects that shaped their lives. And the author’s descriptions of people, places and architecture will have you reaching for your laptop to see the real thing.

The writing is not of the kind that makes you pause while reading and think to yourself, “this is really well-written,” but it has a gentle sophistication and a genuineness about it that you come to associate with Mamah. And while Wright is really a secondary character in this book, Horan shows her knowledge of the man by casually weaving in little details — his love for showy cars, his affinity for capes and stacked heels, his flare at designing clothes, how his interest in architecture came at a young age when his mother gave him Froebel building blocks.

There is plenty of book club discussion fodder here: Is a woman’s duty first to herself or to her family? Did Catherine Wright do the right thing in standing her ground against a divorce? Would the scandal that surrounded the love affair of Mamah and Frank in the early 1900s be the same today? Frank and Mamah talk a lot about living “true” lives; is that something to aspire to or a selfish notion? Was Mamah’s tragic death God’s punishment for leaving her family, as many said at the time? How were Mamah and Frank treated differently in press accounts? Have things changed that much for women?

The multitude of topics aside, at the most basic level, Horan creates a book about love — a story about two people who find their soul mate in each other at the wrong time, and for too short a time. She makes you wish they would’ve found each other sooner.