Audiences can't get enough of fang fiction. Twilight, True Blood, Being Human, The Vampire Diaries, Buffy the Vampire Slayer, Blade, Underworld, and the novels of Anne Rice and Darren Shan--against this glut of bloodsuckers, it takes an incredible film to make a name for itself. Directed by Tomas Alfredson and adapted for the screen by John Ajvide Lindqvist, The Swedish film Lat den ratte komma in (2008), known to American audiences as Let the Right One In, is the most exciting, subversive, and original horror production since the...