I still find "Fahrenheit 451" by the late writer Ray Bradbury as the most memorable book I've read. What it postulates is coming true more and more in the 21st century - from our addiction to entertainment, gadgets, and technology - to the demise of reading long forms of quality literature.
In addition, the book conveys the message that people interact less and less on a personal, face-to-face basis. They seem to be moving away from having real productive and creative conversations. The novel shows that despite all humankind's advances... lasting happiness and freedom is not the end result.
Fahrenheit 451 is a lesson in censorship and a cry for us to preserve books and intelligent discourse through reading, writing, and talking about quality books. It makes me turn off the TV and Internet and sit in a comfortable chair with my favorite libation and savor a masterful book of poetry, a play script, a novel, essay, or short story, as my mind percolates with the concepts provided in these works.