The school and library might not be allowed to have the book, but people who want their kids to learn will give their kids access and their kids will tell others. With the Internet, maybe banning a traditional print book won't be as successful as it was in the 1930s and earlier.
There are a number of websites that offer free access to literally millions of books
Internet Public Library
Library of Congress
OPLIN (Ohio Public Library Information Network)
I worked at a public library when the Internet was just starting up. The Ohio library systems linked, so you can log in to your home library and from there, link to other libraries linked in. This is a nationwide, by now, worldwide network of resources.
With a bit of effort, there are a number of ways to access books. If you can't get them in your state, ask friends and relatives to send copies. Start book clubs. Read to your kids.
Ending this, it is ironic that people seeking knowledge will end up hiding in catacombs like the early christians had to.