I did a talk today about the Orange Book. The Orange Book lays out some very well-structured, very stringent principles for the construction of truly secure systems. The audience for it was DoD and other government procurement officers who needed to buy reliably secure systems for classified processing.
This turns out to be a very personal topic for me. Around the time the Orange Book came out, I was working on a Multics system doing database work for a pharmaceutical company. Multics became one of the first systems to successfully be evaluated under the Orange Book criteria -- at level B2. Honeywell, the maker of Multics, was quite pleased!
They gave these buttons away to all and sundry, and I got one.
I found the fact of a framework capable of assuring a secure computer system fascinating. It has always inspired me to find ways to make systems simpler and so more secure. Vendors to the commercial market today will insist that there's no way to make systems both secure and affordable. Since the primary method of improving a product in its evaluation for an Orange Book rating is to make it simpler, I smell a rat.
One can probably say that my Multics experience in the 1980s inclined me toward getting my CISSP in 2005, and the whole progression of my career since then.