"The K-Factor" is a sci-fi story by author Harry Harrison, published in 1960. A K-factor is a so called "war factor", more precisely a name of an atomic file that can be used in two ways, as with an atomic bomb. Neel Sidorak, our hero, and his team has to constantly guard Earth's safety, as Earth had settled quite a few planets... Thought provoking and entertaining in equal measure!