Several categories of material are generally not eligible for federal copyright protection. These include among others:

• Works that have not been fixed in a tangible form of expression that exists for more than a transitory duration.  It does not have to be readable by the human eye (e.g. content stored on CDs or on a computer hard drive)
• Titles, names, short phrases, and slogans; familiar symbols or designs; mere variations of typographic ornamentation, lettering, or coloring; mere listings of ingredients or contents
• Ideas, facts or discoveries
• Recipes, unless they include substantial literary expression in the form of an explanation or directions, or when there is a collection of recipes as in a cookbook
• Works consisting entirely of information that is common property and containing no original authorship (for example: standard calendars, height and weight charts, tape measures and rulers, and lists or tables taken from public documents or other common sources)
• Works of the federal government, but works created by state or local governments may be protected.
• Works whose copyright has expired