How did Bella find out that Edward was a vampire?

Bella Swan and Edward Cullen are both vampires in Stephanie Meyer's Twilight series of novels. Bella first arrives in a suitably innocent form to her father's town in Washington, called Forks, hoping to meet the Cullen family.

She quickly falls in love with Edward, a fine specimen of a man she thinks, but then discovers all the Cullen (coven) family are vampires. Because of her love for Edward, she wants to be changed into a vampire herself. In this form of fiction, there are very many fans. I suspect that the already long series is not yet over!