This month, a book titled Querkles: Masterpieces will arrive in Australian bookshops. It's one of two titles by Melbourne designer Thomas Pavitte featuring what first appear to be random arrangements of overlapping circles. Colour them in, however, and iconic artworks begin to appear, from da Vinci's Mona Lisa to Duchamp's Fountain. But these clever, colour-by-numbers illustrations aren't child's play; they're for adults. Pavitte, whose 1000 Dot-to-Dot series has sold 400,000 copies worldwide, has published six books and a poster kit in less than two years, and shows no signs of slowing his output.

For those of you who've missed it, colouring books are big at the moment. The bestselling title on Amazon in the US right now is Scottish illustrator Johanna Basford's Secret Garden: An Inky Treasure Hunt and Colouring Book. Its pages unfurl in an intricate, ornate spill of illustrations: birds, flowers, trees, even goldfish. Since its release in 2013, it has sold 1.4 million copies in 22 languages; Basford's follow-up title, Enchanted Forest, is not far behind. Colouring is being touted as the perfect digital detox, and grown-ups around the world are delighting in the chance to sit down with a box of pencils and a book of illustrations and remember what it's like to be five.

Margaret Snowdon from Readings with some of the store's adult coloring books. Credit:Simon O'Dwyer

Colouring books for adults aren't new. Mandala titles featuring designs drawn from Hindu and Buddhist symbolism sat in bookshop "mind-body-spirit" sections back in the 1980s. Roly Allen, from Octopus Publishing House in London, says they were tied to the emergence of the "new age" movement, with niche appeal. Around 2010, however, colouring got cool: titles such as the Gangsta Rap and Indie Rock colouring books (featuring 2Pac and the Shins, respectively) appeared locally, albeit with small audiences.

This all changed in France in 2013, with the emergence of books specifically aimed at relieving anxiety; titles such as 100 Coloriages Anti-Stress proved so popular they began outselling cookery books. Across the Channel and in the US, titles began featuring terms such as "mindfulness" and "calming": Emma Farrarons' The Mindfulness Colouring Book: Anti-stress art therapy for busy people has sold in such numbers that Booktopia is out of stock; Pan Macmillan will publish a second edition later this year. Others include Colour Me Calm, Colour Me Happy and Colour Therapy: An Anti-Stress Colouring Book.