Authorship attribution refers to the process of identifying the author of a document based on the authorial style. It is the most important application of stylometry, which quantitatively measures and analyzes the style of writing. It is an important subject that is relevant to many literary classics. For instance, there has been fierce debate about whether the last 40 chapters of Honglou, one of the greatest Chinese classics, were a later addition written by Gao E instead of the original author Cao Xueqin.