Authors may need hyphens when a long word is interrupted by the end of a sentence. For instance:
"Albert was concerned his earlier actions would conse-
quently land him in hot water."
The hyphen indicates that the word continues on the next line. In this case, hyphens should split the word evenly at syllable boundaries. Consult a dictionary to determine the correct mark for hyphenation.
One of the many uses of the hyphen is in writing names of people with what is known as "double-barrelled names." Many people leave out the hyphens in their names, while others, such as Claude Lévi-Strauss, require it. A person's name should always be written according to the preference of the person in question.
Hyphenate compound modifiers for reasons of clarity and established usage. For example, without the hyphen, the phrase "man-eating shark" reads as if a man is eating a shark.
In other cases, compound modifiers refer to a group of words expressing a sole idea, such as "red-hot lava."
The hyphen must be used after a prefix in three cases. First, when the prefix is followed by a capital letter or number. For example, "anti-American sentiment" and "pre-1800 A.D." Second, when the prefix modifies a word already connected to a hyphen, such as "pre-anti-war sentiments." Third, when the prefix joins a compound word with a white space that will serve as an adjectival phrase, such as "pre-twentieth-century artifacts."