Question about public domain

[jberryhill]

4. "if, through some gross negligence on my part, I allow the first book to lapse into public domain"

I'm trying to imagine what sort of negligence can cause that.

First off, copyright protection is automatic. You do not have to do anything in order to have an enforceable copyright. Federal registration of your copyright provides you with certain procedural advantages in enforcing your copyright, but it is not at all necessary to have enforceable rights.

So, that leaves me stuck at the initial proposition - i.e. loss of copyright through some sort of inaction, given that no particular action beyond authoring the book is needed in order to obtain it.

Secondly, since it is a series of books, you also have a trademark in Dirk Zaxxon as a mark for a series of books. While the title of a single work does not constitute a trademark, the circumstances are different with a series of books, such that the mark functions to signify "that series of books" beyond the title of any one of them.

http://www.rightsofwriters.com/2011/04/copyright-in-fictional-characters-can-i.html

Second, the owner of the rights in a famous fictional character will also likely seek to invoke other legal theories -- particularly trademark and unfair competition laws -- when trying to protect her characters from my unauthorized use. If the name of a character has acquired secondary meaning -- i.e., if the name is sufficiently well known that readers associate it exclusively with a particular author's work -- then the owner may be able to claim that my unauthorized use of the name creates confusion among readers, who may mistakenly conclude that my use of the name is authorized, approved, or licensed by the owner. Confusion as to source, authorization, or endorsement is the essence of an unfair competition claim.