How can you tell whether an old book has been tampered with? First, look at the original work. The original text may be hard to read; if there are annotations that explain the original wording, they are usually reliable; rewritten or interpreted versions reflect the author’s own understanding and are the most likely to be distorted. Second, check who the translator and the compiler are. Translation and compilation are, by nature, a form of re-creation. People with different stances and levels of understanding will end up with different versions of the book. The same *Republic* can differ greatly across different translations. Fourth, read across in parallel: from the same book, compare two different versions, or compare the original text with a modern translation. If the core ideas are consistent and it’s just the way they’re expressed that differs, it’s basically fine; but if the conclusions are completely different, you should be on guard. Fifth, be clear about a real-world fact: truly unaltered texts are almost nonexistent, but the older the book, the fewer times it has been modified.