Basically, it's the US military-industrial complex's hymn to space-based defences, and a major part of Reagan's Star Wars platform. It also has some very nice illustrations of space stations, super shuttles, etc., all of which would be very nice if they hadn't underestimated the costs by several orders of magnitude. No idea if it is rare or not, but there's a lot of stuff in it for anyone interested in space, or in creating a properly researched alternate history in which the US economy collapses under the expense of building it all.
Not sure what I want to do with it, but if I decide not to keep it I'm sure I'll find an SF author somewhere that wants it...