What is the 9th Amendment of the U.S. Constitution about?

What the Ninth Amendment to the Constitution of the United States says is that the rights that were listed in the rest of the document and in the Bill of Rights do not include all the rights that people have.  It says that just because some rights are listed doesn't mean other rights don't exist.

At the time of the writing of the Bill of Rights, the Anti-Federalists were very suspicious of the central government, which is why they forced the Federalists to add the Bill of Rights.  They thought the federal government would take away their rights if it could.

Because they thought this, they wanted the 9th Amendment added in case there were other rights that they had neglected to mention before.  The 9th Amendment was meant to protect these.