Interesting•A 2002 study from Oxford University showed that counting sheep, because it is alerting, does not help you get to sleep.•Charles Darwin's grandfather Erasmus believed that spinning around really fast was a great way to induce the slumber •Hippolytus de Marsiliis (born 1451 Bologna) was the first person to document sleep deprivation as a means of torture.•Humans are the only animals where the two adults choose to sleep together for intimacy. •Humans are the only animals who have sex where they sleep.•Humans are the only animals who voluntarily delay or curtail sleep.•Humans have been sleeping on purpose built mattresses, originally made of plant materials, for at least 77,000 years. •In European folklore the Sandman brings good dreams by sprinkling magical sand onto the eyes of children while they sleep.•One of the functions of sleep is to remove neurotoxins that build up in our brains during the day. •Over a lifetime we will spend approx 220,000 hours asleep, more than any other single activity.•Research indicates that sleep probably first arose sometime in the Palaeozoic era around 500 million years ago.•Sleep inertia is that feeling of grogginess some people have in the morning and it can last for up to 2 hours.•Sleep is primarily of the brain and for the brain; only during sleep can the activity of the brain reduce to a significant degree.•Sleep is the only one of our pleasures that we can only enjoy retrospectively.•Sleep talking mostly occurs during deep sleep and so is not normally related to your dreams.•Sleepwalking happens during deep sleep and is not related to dreaming.•The earliest documented sleep theory is attributed to the Greek philosopher and physician Alcmaeon in 500–450 BC.•The Japanese have the concept, inemuri, of it being socially acceptable to sleep in the workplace, even in meetings.•The phrase ‘sleep tight’ has nothing to do with rope beds but simply means to sleep soundly.•The Tudors thought that sleeping flat out was the position of death, so they slept slightly sitting up hence the bolster pillow.•There are over 90 sleep disorders in the current international classification.•There is a rare and potentially dangerous condition, REM Behaviour Disorder, where people are able to act out their dreams.•There is no scientific evidence that cheese has any positive or negative effect on your dreams. The 2005 ‘sleep and cheese’ survey often mentioned in the media was not a scientific study but a PR exercise.•There is no scientific evidence that sleep is affected one way or another by the earth’s magnetic field.•There is no scientific evidence that your sleeping position tells you anything about your personality.•There is no way of getting the ‘benefit’ of 8 hours sleep in 4 hours.•Tudor beds were short not because the people were appreciably shorter but because they did not sleep flat out, the position of death.Animals •Animals sleep when they have met their other biological needs, i.e. water, food and sex.•Dogs can adapt to their owners sleep patterns, cats cannot or will not.•Gorillas are the only primates that like humans sleep on the ground, each night they make a comfortable nest to sleep in.•Hibernation causes significant changes in temperature control and metabolism and is not in any way related to sleep.•When starving some animals can actually forego sleep in order to obtain food.Driving•A quarter of drivers in sleep-related crashes had less than 6 hours of sleep.•Getting just 5 to 6 hours sleep a night increases you risk of having a car accident 3.3 times.•If you fall asleep at the wheel at 60 mph it will take your car only a few seconds to come off the road.•If you feel sleepy when driving opening the window or turning the music up do not work. Pull over and take a break.•Sleep related car accidents are so dangerous because you cannot take any evasive actions; there are no skid marks on the road.•Sleep related car accidents kill more people than drink driving. •The peak times for car accidents are 2-7 am and mid-afternoon when people are most sleepy.•When driving if have problems focusing, blink frequently or have heavy eyelids pull over and have a nap.•When you are driving the first yawn is too late, pull over and have a breakDreaming•Adults wake up preferentially in dreaming sleep, so if you woke up naturally this morning you will probably remember your last dream.•Don’t worry if you dream you are falling and you hit the ground, contrary to popular belief, you will not die.•Everybody dreams 4-5 times a night but you only remember a dream if you wake during it.•If you never remember your dreams you are probably just a good sleeper. •If you remember many dreams during a night it means that your sleep is being disturbed by something or other.•It has been reported that about 70% of the characters in men's dreams are men, while females seem to dream equally of men and women.•Lucid dreaming is where the sleeper becomes aware that they are dreaming and can to a degree control their dreams. •Men generally have more aggressive feelings in their dreams than women, just like when they are awake.•Most dreams in men are associated with having an erection but this has got nothing to do with the content of the dream. •Most people dream in colour but about 10% dream only in black and white.•Most people have a reoccurring ‘stress’ dream, usually based around situations that they would find stressful or make them anxious. •Nightmares are to the dream world what horror films are to the cinema, they are no more meaningful than other dreams.•People suffering from sleep paralysis often report tightness in the chest or not being able to breathe when they wake.•Sleep paralysis, because of the physical sensations, may make your dream seem much more real. •Some dreams may only last a couple of minutes others may be 40 minutes or so.•The most common emotion reported as being experienced during dreaming is anxiety.•When you dream your dreams are real, so if something happens during your dream your mind may think that it really happened.•When you dream your muscles are paralysed so you are unable to act out your dreams.•You can dream about anything you know or can imagine and so the meaning, of your dreams is personal to you.•You can dream that you are flying because it is not something you can do in real life so is not a threat to your awareness of the world.•You rarely dream about smells, conversations or touch as to do so would compromise your vigilance to external threats.