When should you hyphenate a word?

You should hyphenate a Word when it serves to clarify meaning, particularly in compound adjectives before a noun (e.g., "well-known author"). Hyphenation is also necessary for certain compound numbers (e.g., "twenty-one") and when combining prefixes with proper nouns or other capitalized Words (e.g., "un-American"). Additionally, hyphens can be used to avoid confusion in phrases that could be misinterpreted without them.