The book is a special "journey" by two French authors Léon Riotor and Léofanti through a number of An Nam temples, interviews and talks with the abbots here about "hell" according to Buddhism. Through it, the book reflects the cultural, philosophical and spiritual life of indigenous people in the early 20th century, especially what they envision and believe in a world after death. This book is a valuable document that has been surveyed and described from a Western perspective more than 130 years ago. The two authors interviewed the cultural subject during the trip to Tonkin, with profound and philosophical words.