The surest way to save knowledge just might be etching stone or maybe metals, with some sort of symbology that makes deciphering it easier. Over thousands of years, paper will rot. In a much shorter span of time, electronics will cease to work. But we've learned much about the ancients through stone tablets, like the Rosetta stone. I'm not saying I firmly believe an apocalyptic scenario will occur, although it probably will, but hypothetically if this planet became uninhabitable to our species, I believe etches in hard enduring materials might just be the only medium that could possibly last through the ages. There have got to be some nerds out there who would want to do this as a hobby, preserving as much of our lore as they can on these mediums. If you're out there, make sure to save the Lord of the Rings books. And a bit of history would put a post Anthropocene wasteland into perspective, although hypothetically, should some alien race discover a wasteland Earth in the next few millenia, they would probably have figured out immediately that we'd allowed our rulers to scorch the total environment stupidly. They might think of us like an advanced ant colony with severe neuroses, constructing our collective hive by self destructive means. But a final thought on the subject, there have always been those who did not willingly go along with the highly destructive technics of our present society, most people can't practically live now outside of a toxic consumerism and fossil feul based economy. I insist it's a phallacy to say WE did this to ourselves. The powerful as they always have done before our time, designed the broader society in their own personal interests. And because the strongest militarists tend to dominate everything, it has been brought on our collective species by a small minority of the powerful.