The Surface Web, Deep Web and Dark Web all make up what we know to be the Internet.
The Surface Web is the area of the Internet that we are more familiar. It is the area of the Internet that can be indexed by search engines such as Google, Bing and Yahoo.
The Deep Web and Dark Web also are part of the Internet. The major difference is that these sites do not respond to Search Engine requests, so they are not indexed.
Another important point is the Deep Web and Dark Web are not the same. The Deep Web is primarily made up of information that require some form of authentication to access.