In reading order
The Vampire Diaries: Stefan's Diaries #1: Origins
L. J. Smith
The Vampire Diaries: Stefan's Diaries #2: Bloodlust
L. J. Smith
The Vampire Diaries: Stefan's Diaries #3: The Craving
L. J. Smith
The Vampire Diaries: Stefan's Diaries #4: The Ripper
L. J. Smith
The Vampire Diaries: Stefan's Diaries #5: The Asylum
L. J. Smith
The Vampire Diaries: Stefan's Diaries #6: The Compelled
L. J. Smith