Status of a trademarked but public domain work of fiction
<p>There is a series of books published in the early 20th century.  Copyright on at least some of them have expired; they are in the public domain, and are being widely republished.</p>

<p>However, the descendants of the author have trademarked the names of the main characters.  This trademark can effectively be renewed forever.</p>

<p>How much control does the trademark give them?  I'm interested in whether they can stop the publishing of any derivative works.  Would an "(X) character is a legal registered trademark of (Y)" disclaimer head that off?  Would the setting and story with the trademarked characters stripped out be permissible?</p>

<p>Of course, there's a specific series of books that I'm interested in, but I wanted the general answer because I think this situation is not unique.</p>

<p>Character names can be trademarked in connection with the sale of books. For example, both "Harry Potter" and "Gandalf" are so trademarked. </p>

<p>However, any trademark required continuing use. If the trademark is not actually being used to sell goods or services (currently, within a reasonable past period, or with demonstrable future plans to do so) then an action to enforce the trademark will fail. If the name of the character is part of the title or sub-title of the book, for example "Joe Hero and the evil Empire" or 'The Evil Empire: a Joe Hero book" or is used in marketing the book, that would make the case for applying the trademark stronger. </p>

<p>However, details on just how the name has been used, both by the trademark holders and by others, would make a difference. Anyone seriously interested should consult  an experienced Trademark/IP lawyer in the appropriate jurisdiction (which you don't mention, and which may matter).</p>

<p>Also, if some but not all of the works in the series are still protected by copyright, new works featuring the characters from the series might be considered derivative works of the protected originals, and as such require permission from the copyright holder(s).  Again, details will matter here, as will jurisdiction. </p>

<p><a href="https://www.google.com/search?q=what%20is%20a%20trademark" rel="nofollow">A trademark is</a> </p>

<blockquote>
  <p>a symbol, word, or words legally registered or established by use as representing a company or product.</p>
</blockquote>

<p>In short, I do not think that the family will have an enforceable trademark. Even if they obtained one, the family would have to enforce it and will not likely be successful.</p>

<p><a href="http://www.uspto.gov/sites/default/files/BasicFacts.pdf" rel="nofollow">From USPTO Basic Facts p2-7:</a></p>

<blockquote>
  <p>Generally, marks fall into one of four categories: fanciful or arbitrary, suggestive, descriptive, or generic. The category your mark falls into will significantly impact both its registrability and your ability to enforce your rights in the mark.</p>
  
  <p>Suggestive marks suggest, but do not describe, qualities or a connection to the goods or services. Suggestive marks are registrable and are also  considered “strong” marks. If you do not choose a fanciful or arbitrary mark, a suggestive mark is your next best option.</p>
  
  <p>Descriptive marks are words or designs (e.g., depiction of a television for “television repair services”) that describe the goods and/or services. Such marks are generally considered “weaker” and therefore more difficult to protect than fanciful and arbitrary marks. If the USPTO determines that a mark is “merely descriptive,” then it is not registrable or protectable on the Principal Register unless it acquires distinctiveness-- generally through extensive use in commerce over a five-year period or longer. Descriptive marks are considered “weak” until they have acquired distinctiveness.</p>
  
  <p>Generic words are the weakest types of “marks” (and cannot even qualify as “marks” in the legal sense) and are never registrable or enforceable against third parties. Because generic words are the common, everyday name for goods and services and everyone has the right to use such terms to refer to their goods and services, they are not protectable. Be aware that if you adopt a generic term to identify your goods or services, you will not be able to prevent others from using it to identify potentially competing products or services. In addition, even a fanciful mark that is very strong can, over time, become generic if the owner either starts using the mark in a nontrademark
  manner (see ESCALATOR and ASPIRIN examples, below) or fails to police use of
  its mark properly and take appropriate action. Without proper policing over time, the original owner of a mark could lose any trademark rights it has in the mark.</p>
  
  <p>The USPTO will also refuse registration of a proposed mark for many other reasons, including but not limited to the mark being: a surname; geographically descriptive of the origin of the goods/ services; disparaging or offensive; a foreign term that translates to a descriptive or generic term; an individual’s name or likeness; the title of a single book and/or movie; and matter that is used in a purely ornamental manner.</p>
</blockquote>

intellectual-property public-domain trademark