Joe Hill knew it was only a matter of time before one of the publishing industry's hottest little secrets became common knowledge. He just wished he could have kept it under wraps a bit longer. But when Hill's fantasy-tinged thriller, Heart-Shaped Box, came out last month, it was inevitable that his thoroughbred blood lines as a writer of horror and the supernatural would be out there for all to see. After 10 years of writing short stories and an unpublished novel under his pen name, Hill knows that the world is now viewing him through a different prism - as the older son of Stephen King. Hill, 34, took on his secret identity to test his writing skills and marketability without having to trade on the family name. "I really wanted to allow myself to rise and fall on my own merits," he said over breakfast in this coastal city. "One of the good things about it was that it let me make my mistakes in private." The moniker he chose did not come out of the blue. He is legally Joseph Hillstrom King, named for the labor organizer whose 1915 execution for murder in Utah inspired the song, "Joe Hill," an anthem of the labor movement. His parents, who came of age during the 1960s, "were both pretty feisty liberals and looked at Joe Hill as a heroic figure," he said. Heart-Shaped Box, a title drawn from a song by the rock group Nirvana, is a fast-paced tale of another man with dual identities. Judas Coyne, born Justin Cowzynski, is an over-the- hill heavy metal rocker with a strange hobby: amassing ghoulish artifacts. When Coyne learns that a suit purportedly haunted by a ghost is up for grabs on an online auction site, he can't resist adding it to his creepy collection. Things turn ugly fast after Coyne learns that the suit's occupant is a spooky spiritualist bent on vengeance following the death of his stepdaughter. The book has drawn good reviews, with The New York Times' Janet Maslin calling it "a wild, mesmerizing, perversely witty tale of horror" that is "so visually intense that its energy never flags." And with its cinematic, and bloody, ending, Warner Bros. snapped up movie rights six months before the book hit the market. As excitement percolated about Heart-Shaped Box, so, too, did lingering questions about its author. Inklings about Hill's family background started appearing in online message boards in 2005 when his collection of short stories, 20th Century Ghosts, was published in Britain. Similarities in subject matter and appearance - Hill has his father's bushy eyebrows and the dark beard he sported decades ago - were enough to stir suspicion among followers of the horror genre. "It got blogged to death," Hill recalled. But only when his identity was trumpeted in Variety last year did he realize that the secret was gone for good. "That was really the nail in the coffin," he said. Still, his pen name had a good ride. The editor of Heart-Shaped Box was unaware of the King connection and Hill's agent remained in the dark for eight years before the author spilled the beans two years ago. Hill's decision to follow his father's career should come as no surprise. His mother, Tabitha King, has been turning out novels for decades. His younger brother, Owen King, came out in 2005 with a well-received novella and short story collection that is more literary than horrific and laced with absurdity. Like Hill, Owen King wanted to cut his own path and his book did not mention his parentage. But he decided against a pen name, figuring it would be too much trouble to try to go by an alias when meeting people or having an agent, manager, publicist or personal assistant handle details of his professional life. The only sibling who has yet to make it into print is Naomi King, oldest of the three, who has switched careers from restaurateur to Unitarian minister. But Hill said his sister is working on a nonfiction project: a book-length study of the sermon as literary text and its place in American culture. The King children's interest in books and writing took root early on. "It sounds very Victorian, but we would sit around and read aloud nightly, in the living room or on the porch," Hill recalled. "This was something we kept on doing until I was in high school, at least." IN AN era of celebrity worship, the family has prided itself on being able to maintain as normal a lifestyle as possible despite Stephen King's fame and fortune. Hill and his brother attended public high school in Bangor, Maine, before going on to Vassar College, where they overlapped for one year. After graduation, Hill and Owen King collaborated on a couple of screenplays. They sold one, but it has yet to be made into a movie. The first half of Heart-Shaped Box is set in New York's Hudson Valley, the area around Vassar, where Judas Coyne lives with his latest Goth girlfriend, who 30 years his junior, and two devoted German shepherds. At first, Hill envisioned his tale of a suit with a ghost attached as grist for a short story. But as he added depth and back story to his characters, it ballooned into a novel 10 times longer than what he originally planned. The choice of title was pure serendipity. Hill's initial idea, "Private Collection," went by the wayside when the 1993 Nirvana song popped up on iTunes as the author was getting ready to write the episode in which UPS delivers the haunted suit to Coyne. It was then that Hill decided to package the suit in a heart-shaped box. "Coyne is fiction and (Kurt) Cobain was a real guy," he said, "but I felt that the song fit very well with the book. The song is about a guy who feels trapped and desperate, and the book is about how someone uses music as a hammer to beat at the bars of his own cage." Hill and his wife, whom he met at Vassar, live in southern New Hampshire with their three children. He is reluctant to say much about his private life, recalling how a crazed fan broke into his family's home in Bangor in 1991 and threatened his mother, a frightening episode that evoked the plot of King's earlier best seller, Misery. Stephen King declined a request for comment on his son's novel. "He's trying to go along with Joe's wishes and let him do this on his own," said his spokeswoman, Marsha DeFilippo. But at a recent panel discussion in New York, King told a questioner that he wouldn't rule out a collaborative book project with his son. "I guess anything's possible," he said. "I took them on my knee, read them stories, changed their diapers, and now they're all grown up and they have become writers, of all things. I am really proud of them. I guess we'll see what happens down the road."