Which words in a title should be capitalized?

Solution 1:

This Writer's Block page on capitalization sums up the rules in one page which is the most useful that I have found, basically these rules from the Chicago Manual of Style plus a number of minor rules which are worth reading:

  1. Always capitalize the first and the last word.
  2. Capitalize all nouns, pronouns, adjectives, verbs, adverbs, and subordinate conjunctions ("as", "because", "although").
  3. Lowercase all articles, coordinate conjunctions ("and", "or", "nor"), and prepositions regardless of length, when they are other than the first or last word. (Note: NIVA prefers to capitalize prepositions of five characters or more ("after", "among", "between").)
  4. Lowercase the "to" in an infinitive.

Solution 2:

Title case conventions can vary among different authors or publications. But the most common rule is the following (from yourdictionary.com):

In Titles: Do Capitalize

  • Nouns (man, bus, book)
  • Adjectives (angry, lovely, small)
  • Verbs (run, eat, sleep)
  • Adverbs (slowly, quickly, quietly)
  • Pronouns (he, she, it)
  • Subordinating conjunctions (as, because, that)

In Titles: Do Not Capitalize

  • Articles: a, an, the
  • Coordinating Conjunctions: and, but, or, for, nor, etc.
  • Prepositions (fewer than five letters): on, at, to, from, by, etc.

As I said, this can vary from text to text; you will find exceptional uses here and there.