Books like "God is not great" or "the demon haunted world" have so many examples and are so full of information that it becomes overwhelming. I want to be able to retain information better 
if it comes through repetition how are other people able to read the 2 books i listed and be able to retain the information without having to reread the book?

if it comes through repetition how are other people able to read the 2 books i listed and be able to retain the information without having to reread the book?