While you could read Ms Brennan's books as stand alone novels, you would miss out on the past interactions of some of the characters.  Each book introduces a character or continues the story of a character introduced in a previous book.  I really like this continuity.  I have enjoyed each book  immensely.  I would recommend her books whole heartedly.  What is going to be bad is when I finish all her in print books & have to wait for a new one.  Agony.