There are 9 books in the series by L.J. Smith so far as I can tell although another one needs to come out to close everything up. They are:
Daughters of Darkness
I got them all in three volumes. They are a young adult series but L.J. writes so well that despite the fact that many of stories are the same as far as the soulmate concept goes, with different characters and places, they were very enjoyable and kept you wanting to see what happens next. I really liked them and plan to have them lying around for my daughter to find when she’s a bit older.
The books are about the Night World, a world that is not different from our modern day society but hidden and active within it. Those that are part of the night world, vampires, shape shifters, werewolves, witches, are bound by night world law with two rules; they cannot fall in love with humans and they cannot disclose the night world to humans. The first story introduces us to Poppy who is human and James who is her best friend and unbeknownst to her, a vampire. She finds out she’s not got long to live. James, trying as he might, realizes he’s in love with her and goes against everything he was brought up as to save her. The soulmate concept comes up in each book so you get action, adventure, drama and love. They’re a very nice, easy read and even though I’m way past young adult age, I would read them again.
I went to the author website to find out about the final book. It says it is called “Strange Fate” and it is ‘to come’. The last book in the above series was finished in 1998 so I am hoping that the final does make it’s way out so I can see the final conclusion. Don’t let that stop you though – the books are individual and don’t even have to be read in order but it’s more fun that way because the characters from each book are spattered here and there through the following books.