Nonfiction includes newspaper articles, magazine articles, autobiographies, travel essays, political essays and product reviews.
Many forms of nonfiction start by positing a thesis, then citing pieces of evidence in support of it.
Because nonfiction can be colored by conjecture and opinion, proper citation of sources is very important. A piece of nonfiction backed up by hard data becomes much more persuasive.
Objective nonfiction means nonfiction that presents only concrete, verifiable facts. A list of historical dates is an example of this kind of nonfiction.
Subjective nonfiction is often true, but may be colored by conjecture and opinion from the author. A movie review or employee evaluation is an example of this kind of nonfiction.