Anne Perry works at her craft 12 hours a day, six days a week (she takes Sundays off), year in and year out. The results of her efforts are tangible: Death on Blackheath, out in April from Ballantine, is the 29th in her Victorian mystery series starring Thomas and Charlotte Pitt. Its first installment, The Cater Street Hangman, was released in 1979. But Perry’s written more than one long-running series; in 1990, she introduced William Monk in a series set in an earlier period of Victoria’s reign. Monk’s 20th outing, Blood on the Water (also from Ballantine), hits shelves in September. And in addition to those 49 novels, she also, during those 35 years, wrote five World War I mysteries, two faith-inspired epic fantasy novels that explore the meaning of life (Perry is Mormon), and 11 mystery novellas with Christmas themes (most recently, 2013’s A Christmas Hope). Not yet convinced that Perry is one of the most prolific genre authors since Isaac Asimov? Then add in three YA novels featuring time travel, two adult historicals set in late-18th-century France, and another set in the waning stages of the Byzantine Empire.

Quantity for Perry has not come at the cost of quality. She’s won major mystery awards, including an Edgar and two Anthonys, which demonstrate the esteem of fellow writers and fans alike. And Perry has some impressive stats. She’s a regular on the New York Times bestseller list, with sales of 10 million copies.

At the most recent Bouchercon convention, held in Albany, N.Y. (far from her home in the Scottish Highlands) last September, Perry was the International Guest of Honor. In a broad-ranging interview over tea in a secluded corner of the Hilton Albany, she described the origins of her long career combining murder puzzles with vital social issues.

Perry had struggled for years to write straight historical fiction without success, supporting herself with a variety of jobs: flight attendant, limousine dispatcher, and insurance underwriter. She shifted her approach after her stepfather shared a theory about the identity of Jack the Ripper, but while Perry found that classic unsolved crime—and his speculations—intriguing, she was aware of how many authors had already used the Whitechapel murders as a basis for their fiction. Instead, Perry says, she wanted to focus on “the effects of the pressure of criminal investigations, including the change [that they cause to] relationships, with some old ones eroded, even as new ones are formed,” and the question, “How well do I really know anyone else?” (She later offered her own solution to the Ripper crimes in 2001’s The Whitechapel Conspiracy, a Thomas and Charlotte Pitt book.)

In The Cater Street Hangman, Perry’s debut, she created her very own serial killer: a strangler whose murders were investigated by then–Scotland Yard Insp. Thomas Pitt, in a case that involves the family of his future wife, Charlotte. Thomas and Charlotte’s relationship succeeds despite their very different backgrounds. She was born into wealth and lowered her social status with her marriage to Thomas, who was born to a gamekeeper and rose through the ranks of the police to become a commander. Thus far, Perry has given her readers 16 years in the lives of the Pitts, and she’s distinguished her long-running series by occasionally upending its status quo, as in Thomas’s recent reassignment to deal with political crime, rather than street crime. And Perry has not shied away from having the Pitts encounter the seamier side of life during the ostensibly prim-and-proper Victorian era. The gap between surface appearances and reality in repressed Victorian society has been a theme for Perry from the start. Bluegate Fields (1984) centered on a case of child molestation, and cruelly insensitive attitudes toward sexual assault drive the plot of 2013’s Midnight at Marble Arch. In 1994’s Silence in Hanover Close, Thomas identified a universal need to maintain “masks” and “small illusions” as a prime motive for murder . Not that social commentary trumps traditional mystery elements; the logical solution to Perry’s latest novel, Death on Blackheath, with its mystery of a butchered corpse that may be the body of a domestic missing from the household of a high-ranking government official, is particularly twisted.

Hard-edged storytelling, with raw depictions of poverty and despair, is also present in the Monk books; while Monk shares Thomas Pitt’s humble beginnings (his father was a fisherman), his career was far rockier. Unlike Pitt, who advanced to the very top of the police force, Monk was fired for insubordination, forcing him to work as a private enquiry agent. That job ended after a head injury destroyed his memory; upon recovering, he accepted a position with the Thames River Police, where he’s clashed with child pornographers (2009’s Execution Dock), among other terrible criminals. Perry observes that, tragically, “many of the social problems that Monk and Pitt deal with are still with us today.”

Of all her dozens of books, Perry has reread only two: her fantasy novel Tathea, and its sequel, Come Armageddon, set 500 years later. Both mark a dramatic change in style, tone, and content for Perry; instead of good men laboring to clean up London’s mean streets by bringing wrongdoers to justice, these two books present a heroine seeking answers to life’s big questions. While the existence of these titles may be news to the legions of Pitt and Monk fans, they are the closest to Perry’s heart. Tathea was her first “semblance of a book,” begun when she was in her 20s, and the finished two volumes are the result of a suggestion from her agent, who said, “Write one for yourself.” Perry followed the advice, and dusted off her draft from decades earlier. “I was pleased that there was a lot there I could use.”

Despite the lofty themes, the books are far from being dry religious tracts. Tathea’s opening could hardly be more dramatic: Empress Ta-Thea is woken in the middle of the night by screams to find her palace under assault and her husband and four-year-old son slaughtered. But that violence, which forces Ta-Thea to flee immediately for survival, is the prelude to her epic search. The distraught empress cries out: “Everyone I loved is gone, everything I thought I knew... I want to know if there is any meaning in life. Why do I exist? Who am I?” The answers provided by Perry are derived from her own Mormon faith. PW’s review of the book, which was originally released by Shadow Mountain in 1999, called it “a powerful, inventive meditation on the possibilities that lie in and beyond the origin of religion.”

In discussing her beliefs, Perry cites a Cherokee folktale, in which a grandfather tells his grandson that two wolves are struggling inside of him—one evil and one good. When the child asks which will prevail, his elder tells him, “the one that you feed.” Her belief in free will allows Perry to hope for spiritual progress, both for herself and for humanity at large.

Perry’s writings are an effort to facilitate such progress. Through mystery and fantasy, she aspires to make a difference in her readers’ lives, by teaching them, in her words, “something of the human condition—a wisdom and compassion, an understanding of life that enables feeling empathy for people whose paths may be very different from our own.”