Sparkly, I am not sure if you should be reading goyish books altogether, and I am certainly not giving a haskama to the reading of goyish books, so my words should NOT be taken that way, BUT if you do, and if you want to try to find books that are less treif, you would be better off in general sticking to older books.
You should try to avoid books written after 1990 (or maybe even a bit earlier). There are cases where the same author wrote books in the 1970’s that were relatively not as treif as most goyish books, so people assumed their later books were also okay and found out too late that the later books were completely treif!! So don’t make assumptions about authors.
Shkoyach Sparkly on caring enough about the kashrus of what you read to start a thread about it!!!!