That’s the question someone asked in one of the LinkedIn groups I belong to. During the course of the discussion in the comments, some people seemed to infer that the best way to write a series was for each book to contain a self contained story that was all wrapped up by the time you reached the end, and then the next book would have enough back story and information so that if the reader hasn’t read the previous book, at least they’d know what was going on to some degree. I posted a response to that way of thinking that I believe is worth sharing.
The novels in my series aren’t stand alone simply because that’s the type of a series it is. I wrap up the plot elements specific to that book during the course of the story, but then at the end I lead in to the next major plot element so people will want to read the next one to find out what happens next. I do this for two reasons. First, if each book is a stand alone, then there’s less incentive for people to go on with the series after they finish each one, and second, I really can’t stand books that get mired down in all the back story of things that I’ve already read in the previous book.
Really there are two types of series. The first type would be a series of stand alone books that each have individual stories, and the second type is more like a television series with a running storyline that continues from book to book.
My particular series is the second type. If people want to know what happened before, they should read them in order. You wouldn’t watch the third season of Breaking Bad for example and expect them to keep rehashing stuff that happened during the second season.
Both types of series have their merits and their appeal for different readers, and I personally think there’s more than enough room out there for both.