This is a 13 book long series, it is actually broken down into several smaller series that interconnect. The first part is five books long and is known as the Necroscope series, the second part is the Vampire World trilogy, the third part is the Lost Years series, this is a two part series and the fourth part is the E-branch trilogy.
The overall series is amazing, it blends espionage and horror with a pinch of sci-fi thrown in in the later parts for good measure. It follows the exploits of a group of agents in a special top secret branch of the british inteligance agency. These are extra special agents, they are psychically gifted individuals and use their mental abilities to safegaurd the nations security.
The series begins at the hight of the cold war and the major powers are all developing their own ESPionage agencies. The role of the agency changes dramatically when a specteral visitation occurs in the head office of the british branch. It is Harry Keogh the first Necroscope (one possesing the psychic abilty that allows one to speak with the dead) sending a message from the future warning of event that will soon transpire involving Vampires, the Russian equivalent of thier branch, and an experiment going horribly wrong.
E-branch as the special agency ends up getting called as the books progress change from a primary role as spys to a role of protecting the earth from the vampires and all sorts of nasty things.
The individual parts of the series will be discussed in more depth later in the individual books that make it up, but throughout the course of the various series we meet four diferent Necroscopes, take several trips to the alternate dimension where the vampires originally come from, meet many ancient vampire lords and witness a large number of years pass by as the events unfold.
I have the english publications of the novels and the cover art on the first eleven books that I have is fantastic, by the 12th book the cover art was changed (I believe to artwork by the same artist that did a large proportion of the US releases), and after the 13th was released the 11th was re-relised to match up with the 12th and 13th. So basically that really sucks because my 11th book matches the other major parts of the series, but dosen't mach up with the rest of the sub-series it belongs to.