You just bought a famous book at a nearby bookstore without knowing that the author is your university lecturer

Today, after class, you left your book on the table. When you turned around to look for it, you saw Khuat Tinh Van looking at the book, then calmly looking at you

"Is this book yours?"

Seeing that you were worried and wanted to ask for the book back, Khuat Tinh Van just silently smiled and gave the book back to you.

"Keep it carefully"