Titles are generally considered too short for copyright. A title for one book (as opposed to an entire book series) is usually not covered by trademark. But title-confusion may be litigated as misleading advertising under the Lanham Act or by state unfair competition in some states.
According to the US Copyright site (http://www.copyright.gov/circs/circ34.html
"NAMES, TITLES, AND SHORT PHRASES NOT PROTECTED BY COPYRIGHT
Names, titles, and short phrases or expressions are not subject to copyright protection. Even if a name, title, or short phrase is novel or distinctive or if it lends itself to a play on words, it cannot be protected by copyright. The Copyright Office cannot register claims to exclusive rights in brief combinations of words such as:
*Names of products or services
*Names of businesses, organizations, or groups (including the name of a group of performers)
*Names of pseudonyms of individuals (including pen name or stage name)
*Titles of works
*Catchwords, catchphrases, mottoes, slogans, or short advertising expressions
*Mere listings of ingredients, as in recipes, labels, or formulas. When a recipe or formula is accompanied by explanation or directions, the text directions may be copyrightable, but the recipe or formula itself remains uncopyrightable."