Essay of my Understanding, my Observation and my Thinking

This book is a collection of Chih-Hai Jen's essays written in memory of his 42 years living in China as well as 42 years living in Taiwan.
An essay is, generally, a piece of writing that gives the author's own argument - but the definition is vague, overlapping with those of an article, a pamphlet, and a short story. Essays have traditionally been sub-classified as formal and informal. Formal essays are characterized by "serious purpose, dignity, logical organization, length," whereas the informal essay is characterized by "the personal element (self-revelation, individual tastes and experiences, confidential manner), humor, graceful style, rambling structure, unconventionality or novelty of theme," etc