1. Live off supermarket food as long as possible.
2. Open a can without a can opener.
3. Harness fire.
4. Make yourself a stove.
5. Sterilise water with bleach or UV rays from sunlight.
6. Always wash your hands.
7. Sort your shit out.
8. Grow your own food for when the supermarket stuff runs out.
9. Scavenge diesel-fuelled generators from building sites or roadworks.
10. Use electricity to make some basic chemicals.
11. Redevelop a chemical industry.
12. Keep your car running with wood.
13. Begin relearning the world yourself.
Lewis Dartnell's new book The Knowledge: How to Rebuild our World from Scratch is out now.
You can also explore a load of related material, including how-to videos, at the-knowledge.org.