Gosh, this is one of the few works of Sci/Fi that I can honestly say I am almost ashamed to admit I have read. It is astonishing this work was written in the late 60's. The sweeping plot about a secret society of immortals ruling the Earth, contains scenes of extreme graphic violence, homoeroticism, pornography, promiscuity and smashes just about every taboo imaginable on the way to an exciting (literal) climax.
Honestly a good cigrarette smoke is needed after each chapter.
This book was XXX in its day and few stories could top it today. Worth reading? perhaps but be warned you will require confession afterward.