There are many challenges unique to nonfiction writing – walking the line between a tone that’s credibly serious and one that’s overly dry, organizing and arranging your material so it makes sense and reads well, making reference to real people without getting sued or alienating everyone you know – but one many writers overlook is the need for documentation.

Since there are almost as many varieties of documentation style guides as there are subjects to write about, this article will focus on providing an overview of why and when documentation is necessary.
Documentation amounts to giving credit where credit is due by providing references for any material you cite in your manuscript which came from somewhere else. Not providing such references constitutes plagiarism (presenting someone else’s work as your own), which is not only unethical, it’s illegal. Documentation also serves as a bibliography for your readers, allowing them to find your source material for themselves.
Most people who have been through high school have learned at least some type of documentation, usually in the form of footnotes or endnotes, and those who’ve gone through higher education have had to learn whatever style was appropriate to their area of study. The problem with that is it means many of us harbor resentment and residual confusion about citing our sources because we feel we were “made” to do it. The truth of the matter is that reader and author both benefit from documentation. It’s good for the reader because proper citation allows him or her to find the exact same source the author used, and it’s good for the author because a) it provides ethical and legal coverage for the use of another creator’s words and ideas, and b) citing other established experts increases authorial credibility. In other words, not only does providing documentation make you look more professional, but you also establish an association in the reader’s mind between your name and other names who’ve distinguished themselves in your subject area.
Many of us are also unclear on when documentation is necessary. The short answer to this is “any time you’re presenting work you did not create yourself,” whether that work is in the form of words, artwork, diagrams or illustrations, audio recordings, or anything else you can think of. If you aren’t the person who created the work and you use or make reference to it in your manuscript, you must provide documentation. The only exceptions to this are when you refer to things that are common knowledge (e.g. historical events, folklore, myths or legends) or are widely accepted as fact (e.g. “regular exercise is part of a healthy lifestyle”).
If your work relies on many secondary sources -- in other words, if you didn’t do all the relevant research, studies, tests, interviews, surveys and so on yourself -- you may do a fair amount of paraphrasing and summarizing, but even if you aren’t using someone else’s exact words, you still need to give them credit by providing documentation. Conversely, if you’re using a lot of direct quotes, you need to be sure you’re quoting accurately. Anything you put in quotation marks as something someone else said needs to be exactly what they said, otherwise you’re running into misrepresentation. There are rules that allow for some slight alteration of direct quotations to make them better fit your context, but in general if it’s in quotes it can’t be modified.
So what is it you actually have to do in order to document? The precise answer depends on your publishing venue, whether academic, technical, journalistic, or general. All specialty fields of publication have their own preferred style guides, such as the American Psychological Association (APA) and the Modern Language Association (MLA) – even the Microsoft Corporation has its own publication manual. If your manuscript is intended for the general public, however, you’ll most likely be using The Chicago Manual of Style (Chicago). A more comprehensive list of the various documentation style guides can be found by a quick Internet search (see sidebar).
The broader answer is that for every source you need to have the name of the author(s) or editor(s), the title of the work, and publication information. Some documentation styles use footnotes, in which case the complete bibliographic information appears on the page where it’s referenced, but because this format can complicate the printing process – and because many readers find it intrusive – endnotes are often preferred in commercial publishing. If you’re using endnotes, the complete bibliographic information goes in a separate section at the end (of the chapter or of the entire book) and is usually labeled “References” or “Works Cited” or something similar, while in the text abbreviated citations are used to direct the reader to the appropriate bibliographic entry.
Simple enough so far, but where it can get complicated is in the formatting of the references (the complete bibliographic entries) and citations (the in-text signposts to the references). Each documentation style has its own rules about the order of information, the font style to be used, the punctuation that separates elements in an entry, and how the format of the sources – journal article, book, computer software, interview, film, and so on – should be indicated. Because of the differences in these rules, if you’re working in nonfiction with any seriousness you should invest in the style manual appropriate to your subject area. Internet sources can be extremely helpful, but there’s no substitute for your very own hard copy. After all, sticky notes are ineffective on computer screens but very handy for marking frequently-used sections in books.
While adhering to documentation style guidelines can be time-consuming and confusing, to keep yourself from becoming frustrated bear in mind that there is method to the madness, reasoning behind the seeming randomness of the rules: you’re not just trying to avoid plagiarism and follow guidelines, you’re trying to make things easy for your readers. If readers are engaged in your book and interested in your subject matter, they may well want to check out some of your sources, and it’s part of your job to make it possible for them to do so. If your citations and references are haphazard and sloppy, it’s going to be difficult if not completely impossible for readers to find your source material on their own. And if they’re missing entirely, the message that sends to readers is that you don’t really know what you’re doing.
When it comes time to publish, documentation of your book will be done according to your publisher’s preferences, which may be different from the guidelines you’ve so painstakingly followed throughout your manuscript (publishers’ style guides are generally variations on the standard documentation styles in the relevant fields, though, rather than radically different formatting bibles). Don’t be discouraged – one of the benefits of proper documentation is that all the necessary information is right at hand, and while reformatting it to adhere to a different set of rules may not be a bucket of laughs, the hardest part is behind you.
Is documentation a pain in the neck? Frequently. Is it worthwhile? Always. It’s legally necessary, ethically sound, and it will benefit your readers, which benefits you.