How Should We Then Live?: The Rise and Decline of Western Thought and Culture, by Francis A. Schaeffer, is a decent book to read for those who are unaware of the poison of Humanism.
Back then we had to contend with first-generation humanism, which rejected the Lawgiver but tried to hold on to the notion of Laws. Now we have 2nd-generation humanism, which rejects both Lawgiver and Laws and believes in just making up whatever it wants to believe (such as asserting they can choose their own gender as an act of will rather than accept reality).