Recently John Scalzi (an author for whom I have a lot of time) posted on his blog about the difference in reading tastes between himself and his daughter, While he was disappointed that she wasn't into the same novels that he was, he accepted it as a generational thing, speculating how the classics that defined SF in his time were written for a different audience than the one buying books today.
This is the first old SF novel that I have read since encountering Scalzi's post, and it helped me to appreciate how right he was. It's a book that is book very typical for its time and very different from the novels written today. It's premise is that a group of parasitic aliens (depicted as little more than fleshy balls) land in a then-futuristic 1970s rural America, and proceed to enslave the local population using telepathic control. A scientist who just happens to be working on telepathy stumbles across the invasion and struggles to stop it before the aliens extend their hold over the world.
The novel bears all of the hallmarks of the works of its time: the plot is action-focused, the characters are predominantly male and one-dimensional, and the ending is pretty predictable. And yet it was the fact that it reflected its era that made it such fascinating reading for me. First published in 1954, the novel is a great window onto the concerns of the age, as the alien invasion and takeover (as well as its eventual defeat) all speak to the Cold War-era concerns about invasion and Murray Leinster's commentary on the effects of McCarthyism on the ability to successfully combat it. It's the way in which Leinster's novel so completely reflects its times that makes it a book worth reading, even if the audience for it may be much narrower than it was when it originally came out.