I start this thread in response to a comment by a JW apologist called SimonSays on another thread. He claimed to have read all three volumes of Vindication by Rutherford (my sympathy if true). He further implied that it didn't matter that old JW literature said wrong and stupid things, saying:
I have read all 3 volumes of vindication, and understand it’s reasoning for that era. Of course, I won’t apply it to modern ideology, but the core value still holds.
Well actually that's a bit of a stretch, because the Vindication books promoted the "vindication" doctrine what was arguably the major JW doctrine of the era, a doctrine that was unceremoniously dumped in the 1990s. Rutherford constantly emphasised the vindication of Jehovah's name as the most important issue of all: it was the main reason Jesus came to earth, it was the main reason for preaching, it was the main reason for Armageddon.
So why did JWs dump it in the 1990s? The story goes that it was because hapless Karl Klein was posted to the Writing Deparment. Feeling a bit underappreciated, and wanting to make his mark on official JW teaching, he was scratching around for some "new light" he could invent. He noticed that the scripture that was often used to support the "vindication of Jehovah's name" actually talks about the "sanctification" of Jehovah's name. So Klein pointed out that technically JWs should talk about the sanctification and not the vindication of Jehovah's name. They could still talk about the vindication of Jehovah's sovereignty, but not so much, as it turns out. Thus was dropped the "vindication of Jehovah's name", which had been the central massage of JWs for most of the 20th century.
So no, the "core" of books like Vindication I, II, and III have not been retained. Old JW publications go out of date, not merely in style, contemporary facts, or approach. The very core of old JW publications has been rendered obsolete by their changing teachings.