Authoring Framework

22 Style Guides

This chapter is an adaptation of the Style Guide chapter in the B.C. Open Textbook Authoring Guide, created by BCcampus and licensed with a CC BY 4.0 license.

A style guide helps an author or group of authors be consistent when presenting content to readers. It also saves a lot of work down the line during copyediting.

This chapter focuses primarily on copy. For style considerations that focus on textbook elements, formatting, and layout, please see the chapters in Textbook Organization.

Existing Style Guides

You may want to select the style manual particular to your discipline (e.g., MLA Handbook, APA, Chicago Manual of Style). However, if you are adapting an existing book, you may want to use the citation style chosen by the original author. As you’re writing, try to adhere to the punctuation rules for the citation style you’ve chosen.


The following are a selection of standard punctuation rules:

  • Use one space between sentences (not two) and after a colon.
  • Do not capitalize the first letter of the first word after a colon unless the colon introduces two or more sentences.
  • In displayed lists, always start items with a capital letter. Use end punctuation, such as a period, with full sentences only.
  • Use North American system for quotation marks: periods and commas always go inside quotation marks; semi colons and colons go outside.
  • Use double quotes for all quoted matters. Single quotation marks should be reserved to enclose quotes within quotes (e.g., Mark exclaimed, “You have driven a stake into my heart! Now I truly understand Caesar’s words, ‘Et tu Brute?’ How could you treat me so?”). Some exceptions to this system may be appropriate in specific disciplines.
  • Place footnote numbers outside punctuation (usually a comma or period).
  • Do not use periods in abbreviations, acronyms, and initialisms,  (common exceptions are e.g., et al., etc., i.e.).
  • Do not hyphenate Latin phrases used adjectivally: ad hoc proposal, post hoc analysis.
  • For hanging hyphen constructions (15- to 19-year-olds), do not hyphenate after “to.”
  • Don’t use a period after URLs when they end a reference list entry.

Commas, Commas, Commas

Most style guides use the serial comma. That means a comma placed immediately before the coordinating conjunctive (and, or, nor). Examples:

Serial comma: There were cows, horses, and pigs in the barn.
No serial comma: There were cows, horses and pigs in the barn.

Use commas in numerals over 999 (e.g., 1,000; 45,000).

Being Bold

Bold is reserved for key terms within the text body. It should not be used for emphasis.


  • Use italics for words used as words (e.g., The term vocal cords is often misspelled. What do you mean by nexus?).
  • Use italics for titles of movies, TV shows, and radio programs.
  • Don’t use italics for bands and music channels.

Often words in other languages are italicized in a textbook. However, commonly used words or expressions do not require italics (e.g. ad hoc, vis-a-vis).


Em dashes ( — )

  • The em dash is the standard for breaking a sentence or setting off parenthetical statements.
  • With em dashes, insert a space on either side.
  • In Pressbooks, the em dash is created by using two hyphens. In the book view, two hyphens will look like one long (em) dash.

En dashes (-)

  • There should be no space on either side of the en dash.
  • Use an en dash when expressing a range of years such as birth to death, e.g., 1955-2001.
  • Use between pages (213–223).
  • Use an en-dash (50–100 mg) for number ranges in tables and parentheses.
  • In Pressbooks, use one hyphen to indicate an one short (en) dash.

Measurements and Numbers

Your subject standards and primary audience will determine whether you use the metric (most of the world) or imperial (U.S.) system. For number ranges in text, use the word “to” (50 to 100 mg).

Use numerals:

  • For 10 and greater.
  • In addresses (Suite 2, 400 West Hastings).
  • For dates (May 17, 1948 or 17 May 1948).
  • As designators (day 8, chapter 10, page 9, protocol 5).
  • In figure and table designations (Figure 3, Table 6).
  • For money ($14, $9.97, 6 cents, US$200).
  • For temperatures (20°C).
  • For time of day (11 p.m., 2:45 a.m., 07:30–13:00 ).
  • With units of measure (2 m, 7 in).
  • With percent symbols (0.02%, 99%).
  • With “million” and “billion” ($1 million, 9.4 billion units).
  • For percentages, unless at the beginning of a sentence. Repeat the percentage symbol in a range or series (the incidence varied from 1% to 4%; 6% to 7% of cases).
  • School grades (e.g., Grade 6).
  • Use digits and abbreviations in measurements (e.g., puzzle boxes were 50 cm long, 38 cm wide, and 30 cm tall).

Spell out:

  • Numbers one to nine.
  • First through ninth ordinals unless they include a higher ordinal. Ordinals greater than ninth are expressed as numerals unless they occur at the beginning of a sentence (…in the 12th century, but Twelfth-century monks…). Acceptable suffixes are 21st, 32nd, 43rd, 54th.
  • Fractions, in running text with a hyphen (e.g., two-thirds).
  • Number and percent if at the beginning of a sentence (three percent).
  • For temperatures, use arabic numerals and the degree symbol (37.8°C).