The Book of Enoch says a lot about Biblical Methuselah (the man who lived such a long life) and has several sections authored by him, but few realise there are some secular texts in existence other than the Book of Enoch, very ancient texts, perhaps the oldest texts in the world, which mention someone likely to be Methuselah. These texts are copies of one document called the Instructions of Sharappak. One text is kept in a museum in Chicago, the other in a museum near Oxford in England. They document the wise sayings of the father of Noah written for Noah. They mention the grandfather of Noah, calling him Ubara-Tutu, but this is probably Methuselah from the Book of Enoch and the Book of Genesis. The texts clearly hold him in high regard. Another set of texts supports the identity of Ubara-Tutu, and records that he was king in his time, successor to Enmenduranki, probably the contemporary name of Enoch.
