Harbrace 17d (p. 235 in the 17th edition) The colon
A colon calls attention to what follows. It also separates numbers in parts of scriptural references and titles from subtitles.
(1) A colon directs attention to an explanation, a summary, or a quotation.
When a colon appears between two independent clauses, it signals that the second clause will explain or expand on the first.
No one expected the game to end as it did: after seven extra innings, the favored team collapsed.
A colon is also used after an independent clause to introduce a direct quotation.
Marcel Proust explained the importance of mindfulness: "The true journey of discovery consists not in seeking new landscapes but in having fresh eyes."
Although an independent clause should always precede the colon, a phrase may sometimes follow it.
I was finally confronted with what I had dreaded for months: the due date for the final balloon payment on my car loan.
(2) A colon may signal a list that follows.
Writer frequently use colons to introduce lists
Three students received internships: Asa, Vanna, and Jack.
Avoid placing a colon between a verb and its complement (1c) or after the words including or such as.
The winners were Asa, Vanna, and Jack.
Many vegetarians do not eat dairy products such as butter and cheese.
(3) A colon separates a title and a subtitle.
Collapse: How Societies Choose to Fail or Succeed.
(4) Colons are used in reference numbers.
Colons are often used between numbers in scriptural references.
(5) Colons have specialized uses in business correspondence.
A colon follows the salutation of a business letter and any notations.
Dear Mr. Horner: Dear Maxine: Enc:
To: From: Subject: Date: