The murder mystery puzzle book Murdle by US writer GT Karber has climbed the UK bestsellers chart to become this year’s Christmas No 1 book, beating Richard Osman’s The Last Devil to Die and Guinness World Records for the top spot. Murdle is based on the daily puzzle website Karber developed in 2021, and across the book’s 100 challenges, readers must use codes and maps to decipher who the killers are. It has sold more than 200,000 copies since its publication in June, according to Nielsen BookScan’s chart. Almost a third of those sales have been in the last month, after it was named Waterstones’ gift of the year at the end of November. Arkansas-born, LA-based Karber said his “greatest hope is that this little book brings people together over the holidays, and lets them share some joy with each other”. The Guinness World Records 2024 is this year’s No 2, down from last year, when the 2023 edition took the Christmas No 1 spot. Guinness World Records books have had a total of four Christmas No 1s, a record shared with Jamie Oliver. The chef’s 2023 offering, 5 Ingredients Mediterranean, is at No 13 in this week’s chart. The Last Devil to Die is at No 3 overall, yet marks the seventh time Osman has been the Christmas No 1 in the original fiction category. Britain’s fastest-selling graphic novel of all time, Heartstopper Volume 5 by Alice Oseman came in at No 4 in the overall chart, and No 1 in Children’s. Meanwhile, Booker prize winner Prophet Song by Paul Lynch took the Christmas No 1 in the Irish bestseller charts, selling more than 8,000 copies. Across the year as a whole, Prince Harry’s revelatory memoir Spare was the UK’s bestselling book of 2023, having sold more than 700,000 copies since its publication in January. The paperback edition of Bonnie Garmus’s novel Lessons in Chemistry was the year’s second overall bestseller. The 60s-set debut novel about a chemist-turned-TV chef has been a stalwart of the bestseller charts since it came out in April 2022, and an Apple TV screen adaptation starring Brie Larson began streaming in October. Osman came in at both No 3 and No 4 in the overall Sunday Times bestsellers of 2023, with The Last Devil to Die and The Bullet That Missed respectively. The top cookbook, and fifth overall, was Bored of Lunch: The Healthy Air Fryer Book by Nathan Anthony. Murdle by G.T Karber (Profile Books Ltd, £14.99). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply. 20p from every Guardian Bookshop order will support the Guardian and Observer’s charity appeal 2023, from Friday 8 December 2023 to Wednesday 10 January 2024