Then...
This book was written in 1953, a couple years after WWII. Bradbury was inspired to write this book by the Nazi Book Burnings. The National Socialists Party -Nazi- in Germany during WWII is the burning of any books with had been written or contained anything or anyone who was subversive towards the Nazi administration or ideas.
...Now
People cringe at the idea of burning books. We use books in school, we read books at home, some write books as their job or hobby. Even though we are still reading books, we sometimes are reading them on electronics such as the Kindle or the Nook. No matter how much we deny it we are starting to lean more towards technology and it is becoming a bigger part of our lives. You don't see people reading paperbacks as much as you used to nowadays.
Why is this book a classic?
The book itself reminds us to appreciate books for what they bring to the world in terms of knowledge and information. They also remind us to remember the mistakes we have made in life and how they are made so that we don't make them again. Another reason that this book is a classic is because of Ray Bradbury's prediction of what the world would be like, when it came to books, in the future. Like the walls in the book we now have enormous televisions and we have headphones that are like the Seashells in the book. Books aren't being used as much as they have been nowadays with all the technology that is incorporated into our everyday lives.