Excellent
novel by
Robert Silverberg, published in1972.
The Book of Skulls describes the adventures of four college students coming from completely different social backgrounds.
Eli is the intellectual jew, who found a manuscript called The Book of Skulls, which describes a sect that can offer eternal life to anyone who is willing to submit to their rules and training. Eli tries to convince his friend Ned, who is gay, to travel together into the Arizona desert where he believes they will find the sect. Together they can convince two other students, Oliver, the typical popular sporty student, and Timothy, an east-cost aristocrat son, to join them on their journey. Each of the four boys has a different motivation for the trip, and not all of them truely believe that there is any such things as the Brotherhood of Skulls, or eternal life.
But when they finally find the sect, and begin their training, they find out that only two of them can finish it, and two of them have to die. One has to commit suicide, and the other one has to be killed by the remaining two.
This story can't exactly be classified as science fiction, but rather as a description of American society of the 1970s, a twisted character study on four typical young Americans and an insight into our own humanity and the secrets we all carry within ourselves.
This book would make an excellent movie, I'm still hoping that one day David Lynch, Ridley Scott, or Ang Lee might pick it up...