What is a non-fiction work?
According to a classical definition of knowledge, a well-founded, true belief is knowledge. Knowledge satisfies the requirement of being true, and it can be substantiated. In the Finnish language, one of the original meanings of the word meant knowing the way. Knowledge gets you there.
Accordingly, a nonfiction work – a work of knowledge – is something that is based on publicly and generally accepted knowledge and has the objective of communicating this knowledge to the reader. A nonfiction work may be published in the form of a book but equally well in another form.
What matters is not the publishing format but the core role of a nonfiction work – that of striving to communicate true knowledge to the reader. As to the subject matter, a nonfiction work may deal with any subject within the full range of knowledge. Writers of scientific books, dictionaries or textbooks are all nonfiction writers.