At the B&N Reads blog he tagged "five adaptations that appear to be based on alternate universe versions of their source material," including:
I Am Legend, by Richard MathesonRead about another entry on the list.
A classic novel about a plague that transforms most of humanity into what are essentially vampires, I Am Legend is infamous for the faithlessness of its adaptations: first, an Italian production in 1964 that Matheson had his name removed from, then 1971’s The Omega Man starring Charlton Heston, which removes much of the storyline from the novel. Then things got super weird when the 2007 film version starring Will Smith was released. It was essentially a remake of The Omega Man, making it a poor adaptation twice-removed. The one thing tying all the film versions together is a complete disposal of the meaning behind the title: the philosophical concept that the main character, by dint of being one of the last uninfected humans, has become the stuff of campfire stories—a legend—as a supernatural killer of vampires.
I Am Legend is among Jonathan Hatfull's ten best vampire novels ever, Jennifer Griffith Delgado's top eleven mind-blowing surprise endings in science fiction and fantasy literature and Kevin Jackson's top ten vampire novels.