Adult activity books, which combine puzzles with pop culture and mysteries to solve, have become a publishing phenomenon. Murdoku, with more than 140,000 copies sold in Spain, is leading a booming genre that many associate with digital detox.
It used to be the newsstand crossword, the one you took on the metro or to the dentist’s waiting room. Now it’s a purple-covered notebook with the outline of a house drawn as a sudoku grid, or a hardback packed with questions about Rosalía and Netflix series.
Adult activity books, the latest mutation of the classic puzzle book, have become a publishing phenomenon that is no longer confined to summer, and within them there’s a subgenre that is steadily eating into all the others: solving a murder with a pencil, an eraser and a sudoku grid in hand.
The trend took off a decade ago with colouring books for adults, sold under labels such as art therapy or anti-stress, filled with mandalas, flowers and landscapes. What looked like a summer fad took root, and from there a more ambitious version emerged: the adult activity book, an update of the traditional newsstand puzzle books (crosswords, word searches, sudokus) with an added ingredient that sets it apart: popular culture.
The arrival of smartphones did not spell the end of the analogue genre; what has happened instead is that the two now coexist, just as cooking channels on YouTube have not sunk recipe books or television, which did not kill radio.
Blackie Books and activity books with their own stamp
Blackie Books was among the first to spot the potential. Its adult activity books are already on their 14th volume, one per summer, and have now sold more than 250,000 copies, according to figures from the publisher itself. The latest offers 60 exercises on music, cinema, series, literature, science and sport, designed to “shake off the mental cobwebs”.
Their success led the publisher to branch out the concept: the “Cuaderno Kids”, for children from the age of six; the “Cuaderno Golden”, aimed at an older audience with memory challenges and questions about familiar faces from way back; and the “Quadern”, its Catalan edition, with its own touchstones such as Mercè Rodoreda or the castellers.
Other imprints have carved out their own niche without resorting to crime: Debate has published an activity book signed by “El Mundo Today” that puts the ability to tell reality from fiction to the test, and GeoPlaneta is already on the fifth volume of its travel notebook, complete with playlists and food guides.
Murdoku, the phenomenon that has fuelled a craze for solving crimes
If one book sums up the season, it’s Murdoku. The notebook, with its unmistakable purple cover, has already sold more than 140,000 copies in Spain, and this year it has been seen flying off tables at several spring book fairs. Its mechanics reinvent the classic sudoku: each puzzle places a group of suspects in the squares of a grid, without repeats in any row or column, and the square left empty marks where the victim is; the suspect who shares that square is the killer.
The difficulty ramps up as the book goes on, to the point that some bookshops are already organising live solving competitions. Behind it is Canadian Manuel Garand, a Montreal-based puzzle designer whose work has also been published in the “Financial Times”.
The book has been such a success (and so have those trying to imitate it) that Manuel Garand has even set up a website with the same concept where you can do Murdokus for free. At the time of writing there are 35 puzzles to complete, and this is still a work in progress.
Murdle, Agatha Christie and the rest of the crime genre
The other big name in the genre is Murdle. “Solve the crime” uses a different mechanism: instead of a sudoku grid, it offers narrative clues about suspects, weapons and settings that you have to cross-reference to identify the culprit.
There are already three volumes and a children’s edition; its creator, American G.T. Karber, started out by posting a case a day online before becoming a bestseller in print. Espasa has followed suit with “Los casos de Agatha Christie: 100 acertijos y un misterio por resolver”, the first official activity book about the British author, which invites readers to step into the shoes of Poirot or Miss Marple.
And there’s more: “El crimen del verano” takes the genre to the beach and the pool, with 121 suspects and clues spread across sudokus, crosswords and number pyramids; “Crimigramas”, meanwhile, hides the killer in word searches. None of these formats is new in itself, but when combined with a mystery plot they turn the reader from a passive spectator into a detective, puzzle by puzzle.
Another way to switch off from your phone?
Behind this craze for paper and pencil you can also see a growing weariness with screens. It’s no accident that more and more of these notebooks are marketed explicitly as a way to disconnect digitally, with no notifications and no rush, designed to reclaim that bit of leisure time that used to be swallowed up by the phone.
On top of that there’s a more practical argument: those who follow the trend closely point out that these kinds of games train attention, memory and cognitive flexibility, although no study has yet confirmed exactly what lies behind their success.
No one is trying to make a paper puzzle compete with the sophistication of a videogame; in fact, that’s not the aim. It is more about filling a different gap: a few minutes with your mind engaged and no screen in sight, something more and more people are seeking as part of the pastime itself.
