This is...
Lin Xian flipped to the back of the card.
The back of the card noted its origin.
When this book was discovered in the ancient tomb, this card was already inside, so it was restored and printed along with the book.
Considering that the remains in the ancient tomb were those of a young woman, archaeologists believed that this card was a farewell letter written by the woman, who died of illness, to her lover.
Lin Xian flipped the card back to the front.
Looking at the somewhat heartrending, feigned strong handwriting and tone...
In fact, these few short sentences could already let one's thoughts drift to many things.
The wish of the girl who passed away from illness was actually very simple.
Perhaps she just wanted her book "Introduction to the Cosmological Constant" to be recognized by everyone.
But unfortunately...