The Historian by Elizabeth Kostova

This exquisitely written novel has many suspenseful elements: a sinister librarian, a graduate student whose father has mysteriously disappeared, and several vampires, one of whom is Vlad the Impaler who ruled in the Middle Ages. Yellowed letters and an ancient text offer clues to Vlad’s existence; though countless scholars have risked their reputations and their lives and have failed to prove or disprove that vampires really do exist beyond the legend. This is a thriller with an absorbing story and a bevy of complex characters who keep you on the edge of your seat until you turn the last page.