JDMurray said: The (ISC)2 doesn't expect each candidate to buy all of those books. Several of those references are academic books that are $100+ each. It's more of an academic paper reference list to show where the information comes from. Let the people writing 3rd-party CISSP study guides sift through that list for you.
JDMurray However, this really doesn't matter, as the official CBK books are not the single authoritative source for the contents of any (ISC)2 exam item pool.