A monograph is a specialist work of writing (in contrast to reference works)  or exhibition on a single subject or an aspect of a subject, often by a single author or artist, and usually on a scholarly subject.
In library cataloging, monograph has a broader meaning—that of a nonserial publication complete in one volume (book) or a definite number of volumes. Thus it differs from a serial or periodical publication such as a magazine, academic journal, or newspaper.  In this context only, books such as novels are considered monographs.
The English term "monograph" is derived from modern Latin "monographia", which has its root in Greek.  In the English word, "mono-" means "single" and "-graph" means "something written".  Unlike a textbook, which surveys the state of knowledge in a field, the main purpose of a monograph is to present primary research and original scholarship ascertaining reliable credibility to the required recipient. This research is presented at length, distinguishing a monograph from an article. For these reasons, publication of a monograph is commonly regarded as vital for career progression in many academic disciplines. Intended for other researchers and bought primarily by libraries, monographs are generally published as individual volumes in a short print run. 
In Britain and the U.S., what differentiates a scholarly monograph from an academic trade title varies by publisher, though generally it is the assumption that the readership has not only specialized or sophisticated knowledge but also professional interest in the subject of the work. 
In biological taxonomy, a monograph is a comprehensive treatment of a taxon. Monographs typically review all known species within a group, add any newly discovered species, and collect and synthesize available information on the ecological associations, geographic distributions, and morphological variations within the group.
Book publishers use the term "artist monograph" to indicate books dealing with a single artist, as opposed to broader surveys of art subjects.
In the context of Food and Drug Administration (FDA) regulation, monographs represent published standards by which the use of one or more substances is automatically authorized. For example, the following is an excerpt from the Federal Register: "The Food and Drug Administration (FDA) is issuing a final rule in the form of a final monograph establishing conditions under which over-the-counter (OTC) sunscreen drug products are generally recognized as safe and effective and not misbranded as part of FDA's ongoing review of OTC drug products."  Such usage has given rise to the use of the word monograph as a verb, as in "this substance has been monographed by the FDA".
- Campbell, Robert; Pentz, Ed; Borthwick, Ian (2012).
Academic and Professional Publishing.
'[M]onograph' has become a generic term for a book that is not of a reference type, is of primary material and which may be multi-authored, single-authored, or an edited collection.
- Harrod, Leonard Montague (2005). Prytherch, Raymond John (ed.).
Harrod's librarians' glossary and reference book: a directory of over 10,200 terms, organizations, projects and acronyms in the areas of information management, library science, publishing and archive management (10th ed.). Aldershot, Hampshire, England; Burlington, VT: Ashgate. p. 462.
Archived from the original on 2020-09-03 – via Online Dictionary for Library and Information Science.
For the purpose of library cataloging, any nonserial publication, complete in one volume or intended to be completed in a finite number of parts issued at regular or irregular intervals, containing a single work or collection of works. Monographs are sometimes published in monographic series and subseries. Compare with book.
- The explanation of 'monograph' and 'monogram' in Oxford Advanced Leaners' Dictionary (8th Ed.)
- "The explanation of "monograph" in Online Etymology Dictionary". Retrieved 5 February 2021.
- Williams, Peter; Stevenson, Iain; Nicholas, David; Watkinson, Anthony; Rowlands, Ian (2009). "The role and future of the monograph in arts and humanities research". ASLIB Proceedings. 61: 67–82. doi: 10.1108/00012530910932294.
- Thompson, John B. (2005). Books in the Digital Age: The Transformation of Academic and Higher Education Publishing in Britain and the United States. Cambridge: Polity Press. pp. 84–85. ISBN 978-0745634784 – via Internet Archive.
- Vines, Sydney Howard (1913). "Robert Morison (1620–1683) and John Ray (1627–1705)". In Oliver, Francis Wall (ed.). Makers of British Botany. Cambridge University Press. p. 22 – via Wikisource.
- "DOCID:fr21my99-6", Federal Register, Rules and Regulations, 64 (98), pp. 27666–27693, May 21, 1999, archived from the original (TXT) on 2017-02-01