I am currently reading a book called "Philosophy of the Common Task" by Nikolai Fyodorov. It's a very obscure book that I spent too much on (I really regret it now). But the book is really interesting, and the guy who wrote it (Fyodorov) had some really interesting thoughts. Pretty much he was into cosmism and transhumanism, and how we humans need to unite (even the dead, as in the resurrection of humans) to ascend into the higher reaches of space and achieve physical immortality. I don't remember much of it as I still haven't finished the book. But the guy had some really strange and interesting ideas, I mean he was alive during the 1800s and he was respected by Tolstoy, Dostoevsky and many more and was even called the "Socrates of Moscow." What's also funny is that he was a Christian and he influenced the Russian space program. So yeah, really interesting guy. But you will never find his book, why? Cause it was only translated once into English and was never translated again, it does exist in Russian and it's quite cheap in Russian. So if you can read Russian might as well buy it.