7 Book Series the Original Authors Haven't Finished

Writing a novel is no small feat. Tackling a full book series is even more daunting, which explains why some of the most talented authors in history have left their stories incomplete. Whether the authors lost interest, died before finishing, or are working on the next installment (they promise), these book series haven't been wrapped up yet.

1. A Song of Ice and Fire

George R.R. Martin hasn't published any new installments of his saga A Song of Ice and Fire since publishing A Dance with Dragons in 2011. His next planned book, titled The Winds of Winter, is one of the most highly anticipated novels of all time, but a date hasn't been set for its release. Game of Thrones became a television sensation in the time since A Dance with Dragons was published, and Martin has found himself busier than ever. "Writer’s block isn’t to blame here, it’s distraction," he told IndieWire in 2014. "In recent years, all of the work I’ve been doing creates problems because it creates distraction." Even if he does get around to finishing The Winds of Winter, A Song of Ice and Fire still won't be finished. He plans to write an additional book, A Dream of Spring, to complete the series.

2. The Parable Series

Unlike other science fiction books from Octavia Butler, her Parable series takes a grounded, realistic look at the future. The Parable of the Sower and The Parable of Talents are set in the rapidly destabilizing America of the 2020s and 2030s (decades ahead of when the books were published in the 1990s). For the third book in the trilogy, Butler had planned to venture into hard sci-fi and finish the story on a distant plant. She wasn't able to realize her vision, however. Depression and writer's block led her to abandon The Parable of the Trickster and work on Fledgling, the book that would be her last novel. She died in 2006 before completing the Parable saga.

3. The Dune Chronicles

The sixth novel Frank Herbert contributed to the Dune Chronicles ends in a cliffhanger. The author had planned a follow-up to Chapterhouse: Dune, but he died in 1987 before he could complete his science fiction series. Though Frank Herbert's son Brian and novelist Kevin J. Anderson teamed up to write several Dune prequels after his death, the series as the original author planned it never received a proper ending.

4. The Millennium Series

All three novels in Stieg Larsson's Millennium trilogy were published posthumously. Larsson had planned 10 books for series, and he had completed The Girl with the Dragon Tattoo, The Girl Who Played with Fire, and The Girl Who Kicked the Hornets' Nest before he died of a heart attack in 2004. His sudden death didn't prevent these books from being released, but it did ruin any hope of seeing more installments from the original author. Readers got three new Millennium books from a different author, David Lagercrantz, in the 2010s. Larsson reportedly left behind an unfinished manuscript of a fourth book, though it remains unpublished.

5. The Kinsey Millhone Alphabet Series

The structure of Sue Grafton's Alphabet series meant it had a clear endpoint. The title of each mystery novel featuring detective Kinsey Millhone had a title based on a different letter, starting with A is for Alibi published in 1982. Sue Grafton had been working on her series for 35 years when she died in 2017. Her most recent novel, Y is for Yesterday, hit shelves earlier that year, and she had yet to start writing the last book planned for the series, Z is for Zero. Her family has no plans to finish the series without her. Her husband Steve Humphrey said in a statement: "There will just be a 25-letter alphabet, I'm sorry to say."

6. The Exiles Trilogy

Fantasy readers have waited patiently for the final installment in Melanie Rawn's Exiles series for 25 years. Following the release of The Ruins of Ambrai in 1994 and Mageborn Traitor in 1997, Rawn had planned to complete the trilogy with The Captal's Tower. Personal issues, including depression, have prevented her from returning to the world. But that doesn't mean Rawn hasn't been busy; she's published several books since Mageborn Traitor, and she's assured Exiles fans over the years that she hasn't forgotten about the series.

7. Dirk Gently

In 1987, the author best known for The Hitchhiker's Guide to the Galaxy published the first book in the Dirk Gently series. Douglas Adams's novels Dirk Gently's Holistic Detective Agency and The Long Dark Tea-Time of the Soul follow the psychic, time-traveling detective the series is named for. Adams started a third book titled The Salmon Of Doubt, but after discovering it "really wasn't working," he reworked the ideas into the Hitchhiker's Guide universe. He was unable to finish the project before his death in 2001, but the chapters he completed were published posthumously along with his miscellaneous writings under the title The Salmon Of Doubt.