Daydreaming has long been criticised as the pursuit of slackers and time-wasters. For a while in the 1950s it was thought excessive daydreaming could lead children into psychosis (a theory that has since been thoroughly disproved).

Actually, Albert Einstein’s daydreams gave us the theory of relativity, while Mark Twain’s daydreams produced the unforgettable story of Huckleberry Finn.

Daydreams are more than escapes from humdrum afternoons: they are critical workings of the human mind. They bring us wisdom and creativity. They’ve been the flicker of life for pretty much any great work of art, film, literature or project you can name. Learn to embrace daydreams and you can get powerful insights into the world and your future, and maybe just create something beautiful of your own.

Daydreaming is more prevalent than you might think. Experts now believe it’s is the normal, default state of the brain. A study from Harvard University published in 2007 in Science found that unless there is an engaging problem in front of you, your mind is likely to be wandering. So if you’re making a sandwich, you might be thinking about a situation at work – because making a sandwich is easy and doesn’t need much attention.

In the late 1960s, Professor Emeritus Jerome Singer from Yale University was a pioneer researcher on the topic. "The most common type of daydream is constructive daydreaming," he says. "You might think mundane things like, What am I going to have for dinner tonight? and then imagine what you’d like to cook, and whether you need to buy the ingredients, and so on."