Reading Abraham Lincoln: Vampire Hunter

Just finished reading Abraham Lincoln: Vampire Hunter (2010) this week. Author Seth Grahame-Smith offers an interesting premise about vampires in America and Lincoln's decades-long quest to eradicate them. The narrative jumps around a bit, but the book is an easy read. The ending (set in the 1960s) offers promise for a sequel (now available). The publisher's website includes a trailer for the original book and a mock documentary supporting its claims. 

For vampire fans, while we really get into Lincoln's head, we don't get much detail into the history of the undead (besides the suggestion of an emigration from Europe following the activities of Countess Bathory) and nothing about their natures (i.e. are the demonic?) besides that some are good (abolitionist/prohuman vampires) and some are bad (those allied with the South/Confederate States). There is also little information about how they die; they don't appear to decay, and there is at least one reference of hunters having to bury the body.