Monograph

A monograph is a work with scholarly ambition, written on a single subject.

• Its original use, at the start of the nineteenth century, was in biological sciences, where it very precisely meant 'a thorough account of a single species or genus'.
• This meaning was extended by the middle of the century to "a detailed written study of a single specialized topic (distinguished from general studies in which the topic is dealt with as part of a wider subject)" (OED). This could be a short article, a section of an encyclopaedia or a book, sometimes of more than one volume in length.

By the beginning of the next century, librarians were using it to mean 'an independent item, not part of a series or periodical'.

• In academic use in the twenty-first century, a monograph is normally a single volume book produced as part of the writer's progression into full acceptance as a serious scholar. It is the step required, or advised, after the publication of one or more articles in learned journals. Recently graduated PhDs often adapt their theses for publication: such a book is a monograph.

One of the characteristics of the great fictional detective Sherlock Holmes is the large number of monographs he produced, on subjects as varied as classifications of soils in particular localities, different types of tobacco ash, the polyphonic motets of Lassus, secret writings, the analysis of various tattoos and A Practical Handbook of Bee Culture. Many of these, if not the last, should be envisaged as pamphlets rather than weighty tomes.

Etymological note; Monograph comes from the Greek μόνος (monos, ‘single’) and γραφή (graphē, ‘writing’).