No, Really, WAR IS PEACE.

"The effect would be much the same if the three superstates, instead of fighting one another, should agree to live in perpetual peace, each inviolate within its own boundaries. ... A peace that was truly permanent would be the same as a permanent war. This ... is the inner meaning of the Party slogan: WAR IS PEACE." -- Page 177

The Theory and Practice of Oligarchical Collectivism by Emmanuel Goldstein is probably the only book I've ever read within a book, and I must say that it didn't disappoint.  I would certainly suggest to anyone reading 1984 that he read this section of the novel rather than skip it (as Mr. Costello has allowed classes to do in the past, psh) for two reasons:

1. It gives valuable insight into the reasons for the way Inner and Outer Party members live through the historical background and significance of the wars against Eurasia and Eastasia, thus leading to a more immersed reading of the rest of the novel, and
2. It contains some interestingly deep thoughts on collectivism, corporatism, and, of course, communism, all of which, among others, contain principles that Orwell was trying to prevent by writing of the potential dangers they imposed.

Basically, this is some pretty scary stuff.  In the context of the novel, it's even scarier to realize that this 'heretical' book was written by none other than the Party itself.  Once again, this idea requires doublethink.  For O'Brien, and the others, to have been able to write a book that, to my best judgement, truthfully objects to the values of the Party and lays out substantial reasoning supporting that argument, they had to acknowledge that its sole purpose was to be an entrapment device and that the logic contained therein was unorthodox.  As O'Brien tells Winston later in the Miniluv, regarding the truthiness of the book, it is "[a]s description, yes. The programme it sets forth . . . is nonsense".