It's the label that every author dreams of having on the front of their book: "Sunday Times Bestseller".
The newspaper produces weekly sales charts for hardback and softback book sales in the UK.
And they recently announced which books sold the most in 2023.
Here are the top 11. You can see the full list here.
1. Spare by Prince Harry, The Duke of Sussex
The book that everybody was talking about in 2023 inevitable tops the charts with an amazing 700,962 copies sold in hardback. "For the first time, Prince Harry tells his own story, chronicling his journey with raw, unflinching honesty. A landmark publication, Spare is full of insight, revelation, self-examination, and hard-won wisdom about the eternal power of love over grief."
2. Lessons in Chemistry by Bonnie Garmus
Assisted by a major Apple TV series starring Brie Larson, Lessons in Chemistry was the best selling work of fiction in 2023, thanks to shifting 466,628 paperbacks. "Chemist Elizabeth Zott is not your average woman. In fact, she would be the first to point out that there is no such thing. But it's the early 1960s and her all-male team at Hastings Research Institute take a very unscientific view of equality. Forced to leave her job at the institute, she soon finds herself the reluctant star of America's most beloved cooking show, Supper at Six."
3. The Last Devil To Die: The Thursday Murder Club 4 by Richard Osman
The popularity of television host Richard Osman's series of crime novels set in a retirement village shows no sign of letting up anytime soon. The fourth book was another hit, with 419,456 hardbacks sold. "Shocking news reaches the Thursday Murder Club. An old friend in the antiques business has been killed, and a dangerous package he was protecting has gone missing. As the gang springs into action they encounter art forgers, online fraudsters and drug dealers, as well as heartache close to home."
4. The Bullet That Missed: The Thursday Murder Club 3 by Richard Osman
A total of 387,181 paperback sales gives Pointless host Richard Osman a second entry in the top five with the third in his fun series of crime novels. "It is an ordinary Thursday and things should finally be returning to normal. Except trouble is never far away where the Thursday Murder Club is concerned. A decade-old cold case leads them to a local news legend and a murder with no body and no answers. Then, a new foe pays Elizabeth a visit. Her mission? Kill...or be killed."