On the Art of Proper Handling of the Titles
Title case (sometimes referred to as “headline case”) is a way of capitalization used when writing the titles of literary works or works of art in English. All words in the title are then capitalized, except for some minor words (such as articles, short prepositions, and some conjunctions) that are not the first or last words of the title.
Rules and standards
There are different rules for which words are major, and what should be capitalized. The most popular and widespread rulebooks include the Associated Press Stylebook, Chicago Manual of Style, Modern Language Association Handbook, or American Medical Association Manual of Style Capitalization Rules.
The title case is opposed to the sentence case, where only the first word and proper names start with a capital letter. There is also the all-caps case, where everything gets capitalized.