It is a means to an end, and its entire purpose is to (1) set up the end of the series in book 5, and (2) tackle two other boroughs of New York City. And maybe to turn everything on its head to make you salivate for the end.Charlie Huston's fourth installment in the Joe Pitt series, Every Last Drop, delivers on the wit, the tough-guy approach, and more than delivers on the revelations. Just how do all those Coalition vampires get their blood? The answers aren't easily digestible, and it's the kind of information that can blow open the whole lid on the existence, and future, of vampires. The down-side is that we have to wait for the finale, but lucky for us, Huston has a history (the previous book was published in 2007) of keeping things short, sweet, and bloody.