Sarah J Maas’s long-awaited return to her bestselling romantasy series has smashed UK sales records, with A Court of Splintered Harmony becoming the fastest-selling adult fantasy novel since accurate records began in 1998.

The novel, the sixth in Maas’s A Court of Thorns and Roses (Acotar) series and her first return to it in more than five years, sold 188,914 copies in the UK between publication day on 27 October and 31 October, according to NielsenIQ BookData. That also makes it the fastest-selling hardback novel since Dan Brown’s Inferno, which sold 229,000 copies in its first week in 2013.

“Harry Potter has the record for the highest ever weekly sale for a fantasy novel, but it’s the biggest sale since our records began [in 1998] for an adult fantasy novel,” said Philip Stone of NielsenIQ.

Rebecca Yarros’s Onyx Storm held the previous record, selling 155,141 copies in its opening week in January 2025. According to Maas’s publisher, Bloomsbury, A Court of Splintered Harmony is also the biggest single week of sales for any adult fiction title in the UK since Harper Lee’s Go Set a Watchman in 2015.

The US author is one of the most prominent writers of romantasy, the genre blending romance and fantasy that has come to dominate bestseller lists in recent years. Strong sales of romance and fantasy helped UK fiction revenue pass £1bn for the first time in 2024. The genre’s readers are largely young women, and much of its growth has played out on TikTok, where hashtags related to Maas have more than 14bn combined views.

The novel went straight to No 1 in the UK’s overall book chart, Maas’s third time at the top. When she last topped the chart, in January 2024, House of Flame and Shadow, part of her Crescent City series, sold 44,761 copies in its opening week.

Globally, A Court of Splintered Harmony sold 1.7m copies in preorders and first-day sales, according to Bloomsbury. The figure counts English-language print and ebook editions in the US, Canada, the UK and Australia, but not audiobooks or translations. Maas’s global English-language sales across all her series now exceed 100m copies.

Fans turned out in force for the release, with bookshops across the UK hosting parties and opening past midnight. Waterstones alone hosted 60 midnight launches and 80 early openings and release-day parties across its shops.

“As one of our most pre-ordered books of the year, excitement for Splintered Harmony was at fever pitch, and the astounding first week of sales has reflected this,” said Lucy Jakes, the science fiction and fantasy buyer at Waterstones. “It was amazing to see the hype translate into thousands of Sarah J Maas fans gathering in bookshops.”

Acotar is one of the biggest franchises in publishing. The first book, which reimagines Beauty and the Beast, came out in 2015, and its sequels follow Feyre through the faerie realm of Prythian.

The new book is the first part of a four-part story. The next two parts are contained in A Court of Forgotten Melody, out on 12 January.