Suppose you know from good sources that there is going to be a huge catastrophe in the very near future, which will result in the near-extermination of humanity (but the natural environment will recover more easily). You and a small group of ordinary men and women will have to restart from scratch.

You have a limited time to compile a compendium of knowledge to preserve for the new era. What is the most important knowledge to preserve?

I am humbled by how poorly my own personal knowledge would fare.