body: I'm working on a series of books that I plan on publishing only as epubs (e.g. Kindle). Just as books are marketed as "Penguin" or "Alfred Knopf," I'd like to get a trademark that I can list on my books.
  
  
  I've learned that can't get a trademark for a single title. You have to have a **series** of titles to qualify.
  
  
  However, it isn't clear to me what is meant by "series." Do they mean well define series, like "My Horse Book," "My Horse Book II," etc.? Or does series in this case simply refer to multiple books?
  
  
  I'm already working on half a dozen books focusing on a variety of topics, including state symbols, political science and philosophy.
  
  
  
title: What constitutes a series of books for trademark purposes?