The product is a hardcover book titled "Katabasis" by author R.F. Kuang, published in 2025. It is the instant No.1 Sunday Times best-seller and is written in English. The book is a standout in the world of literature, capturing the attention and admiration of readers with its compelling storyline and engaging narrative. As a result, it has rapidly ascended to the top of the charts, making it a must-have for book enthusiasts and fans of the author.