Sleep has hardly changed since Paleolithic humans snoozed soundly in their caves. While sabre-toothed tigers were their biggest night-time worry, today it's stress and social media that keep us awake, but the solutions are the same, and sleep therapist Dr Merijn van de Laar offers understanding and advice to have you sleeping better within weeks.

How to get a better night's sleep in 3 weeks:

• Don't believe everything you read or hear about sleep
• Let go of the 8-hour rule
• Use the simple sleep diary in the back of this book to record your sleep pattern over 3 weeks
• Discover your personal sleep needs
• Examine your attitude towards lying awake at night
• Shorter total bed times might be better
• Focus on the reason for lying awake rather than on the reason for not sleeping
• Reduce stress
• Keep regular bedtimes
• Follow the rules of nature
• Respect your personal circadian rhythm
• Don't tempt the night-time ghosts

Human sleep as we know it today evolved hundreds of thousands years ago, to suit a hunter-gatherer lifestyle. It's not always compatible with our modern lives, but remains an essential function, vital for our health, well-being and daytime functioning. In this groundbreaking new book, Dr Merijn van de Laar investigates the origins of sleep based on archaeological findings and anthropological studies in contemporary hunter-gatherers, looking at the major discrepancies between our primordial bodily needs and our current sleep-inhibiting behaviour.

Cave dwellers lived in balance with the forces of nature. They had adapted perfectly to environmental influences such as light, temperature and seasonal variations. The way they ate and moved during the day must have had a positive effect on sleep quality. We need to look to their example, and adjust our eating, exercise, light, temperature and, last but not least: our expectations towards sleep. By taking on board the ancient wisdom of our ancestors, we will improve the quality of our sleep, the way our bodies were designed to do it.