Paper, pencil and murder mysteries are giving traditional puzzles a new cultural life.
MADRID, SPAIN
Adult activity books have become an unexpected force in Spain’s publishing market by combining familiar puzzles with popular culture, humour and interactive mysteries. Once associated mainly with summer holidays or newspaper stands, these books are now sold throughout the year as an analogue form of entertainment for readers seeking a temporary escape from screens.
The trend developed from the adult colouring-book boom that began approximately a decade ago. Publishers gradually expanded the format beyond mandalas and stress-relief exercises, introducing crosswords, quizzes, word searches and logic games connected to music, television, literature, science and sport. Blackie Books has reached 14 volumes of its principal adult activity series and reports total sales exceeding 250,000 copies.
The most visible success is Murdoku, a murder mystery constructed around modified sudoku puzzles. Each grid contains suspects who cannot be repeated within the same row or column. The remaining empty square identifies the crime scene, while the corresponding suspect reveals the killer. Created by Montreal-based puzzle designer Manuel Garand, the book has sold more than 140,000 copies in Spain, according to figures reported by its publisher.
Its popularity has encouraged bookstores to organise live competitions and helped establish crime-solving puzzles as a distinct publishing category. Murdle, created by American author G.T. Karber, uses narrative clues about suspects, weapons and locations instead of sudoku grids. Other titles place Agatha Christie characters, word searches, number games and beach mysteries inside similar detective frameworks, transforming readers from passive consumers into participants.
Publishers are also adapting the model for different audiences. Blackie Books offers editions for children, older readers and Catalan-speaking consumers. Other companies have introduced travel notebooks, satirical exercises and activities that challenge readers to distinguish real news from invented stories. The commercial appeal lies in combining recognisable subjects with tasks that can be completed individually or socially.
Digital fatigue is frequently presented as the principal explanation for the boom, but no definitive study has established why these books are succeeding. Solving puzzles may engage attention, memory and cognitive flexibility, yet such activity should not be confused with a clinically proven treatment or guaranteed protection against cognitive decline. Their immediate attraction is simpler: they offer structured entertainment without notifications, algorithms or continuous scrolling.
La verdad es estructura, no ruido. / Truth is structure, not noise.