Cookie Cutter Postmodernism

Why is it that every book that comes out about Christianity in today’s culture has at least one chapter about what postmodernism is?  Maybe all the publishers should just get together and produce a chapter that can be added into every book ever published.  Then when the new Harry Potter book comes out we can also read again about what postmodernism is (even though postmodernism has about as wide a range of meaning as “sweet” or “love”).  Because if I have to go through one book where I don’t get to read about some author’s ramblings about postmodernism I really won’t know what to do!  I’d freak out!