Beloved playwright Tennessee Williams wrote some of his greatest plays during the 15 years he spent with his lover, Frank Merlo.

The muse-like inspiration that developed during their relationship is the subject of author Christopher Castellani’s new book, “Leading Men.”

The book is a fact-based fictionalized realization of the couple’s life and the creative boom that Williams experienced during those 15 years with Merlo.

“I wrote the book to try to figure that alchemy between those two men and how that gave rise to some of the greatest work,” said Castellani during an interview with Boston Public Radio Wednesday.

Castellani did extensive research to portray Merlo and Williams accurately. He said he wanted to write within the “cracks of history.” At the end of the day though, fastidious date references alone could not capture the couple’s reality.

“The most important thing is that it was emotionally true between these two characters,” Castellani said.