Series Writing

A friend in a writing group has written a romance with an intriguing twist -- and no, I'm not saying what it is until it's pubbed (and I'm sure it will be at some point, she's getting requests for fulls from both editors and agents because it's really quite good). BUT... she mentioned that she's considering making the twist into a series based on the same twist. I think it's a fantastic idea.

And it got me to thinking about writing series.

I like to read series. It's a little like going home again when they're done well. You get to know the family of characters and it's wonderful to revisit them on a regular basis. I've read all of Nora's "In Death" books, and though some are certainly better than others, I've grown quite attached to her characters (especially Peabody) so will keep reading until I don't like them anymore.

I have some secondary characters in all of my WIPs that I have come to love and would like to see how their lives turn out. I'm toying with an idea of linking at least two if not all of my books together. Conveniently, the one that takes place in Colorado has characters from Boston, which is where Liv is from in my current WIP. In any case, I know my brain is turning the idea over and may surprise me with a valid idea at some point.

How about you? Do you like reading series? If so, which ones are your favorites? If not, why?

Have you considered writing a series? Why?