A monograph is a work of writing upon a single subject, usually by a single author.

It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article.

It is by definition a single document that forms a complete text in itself. An author may therefore declare his own work to be a monograph by intent, or a reader or critic might define a given text as a monograph for the purpose of analysis. Normally the term is used for a work intended to be a complete and detailed exposition of a substantial subject at a level more advanced than that of a textbook. Monographs form a component of the review literature in science and engineering.
Librarians consider a monograph to be a nonserial publication complete in one volume or a finite number of volumes. Thus it differs from a serial publication such as a magazine, journal, or newspaper.（出典：Wikipedia）