I read the original Vampire Diaries books many years ago, I loved them, along with the newer books released. With the recent explosion in Vampire related media, the books were adapted as a TV series. I really liked the series and found the changes to the original novels fresh and very well done. Stefan's Diaries is written by the book series' author but follows the altered TV series story. In the original novels, Stefan was actually born in Renaissance Italy - The 1600's and came to Fells Church (as Mystic Falls was known as in the books) without any prior involvement with the town. The TV series changes Stefan's past to him being alive during the American Civil War in the early 1860's, living in Mystic Falls. Which to me makes much more sense as to why he returns almost 150 years later. L.J Smith has done a great job adapting her original story to fit the TV series' time and location while still retaining the essence of the previous novels.
Stefan's Diaries is set in 1864 and ties in brilliantly with the flashback scenes in the TV series' first season. We get to learn exactly what life was like for him and his brother Damon during this time; and an insight into their relationship and how it fell apart.
I reccommend this book for anyone who is a fan of the TV series and thus familiar with the adapted storyline. It gets in to Stefan's head and expands on the flashbacks from the TV series. If you haven't seen or don't like the TV version, it still works as a stand alone story. Fan's of the original novels I'm sure will like it too, though many things have changed the core plotline is essentially the same.