Colouring was a popular pastime for grown-ups even in the 18th Century, say scientists who have discovered a rare 256-year-old adult colouring book in the US.
The book, titled 'The Florist', features drawings of 60 plants and flowers along with instructions for how to paint them.
It was printed around the year 1760 by Robert Sayer and the title page points out that the pages are "intended for the use and amusement of Gentlemen and Ladies."
"Our library catalogue listed it (the book) with the full title: 'The florist: containing sixty plates of the most beautiful flowers to which is added an accurate description of their colours with instructions for drawing and painting," said Pool, curatorial assistant at the Missouri Botanical Garden in the US.
The book was mass produced, but fewer than 10 known copies remain, Markeya Thomas, from Missouri Botanical Gardens told 'CNN'.
"It's kind of fun to think about colouring being a popular past time for adults in the 18th century and again today, so it's of some culture significance," said Pool.
The Garden's copy of "The Florist" has not been coloured in and has been fully restored to preserve its pages.
Its pages were used to press plants - evident by the residual images on blank pages - and the name 'Albert' is written on the back of the title page.