What does it mean for HTTP to be stateless?

I'm currently trying to learn networking using

James F. Kurose, Keith W. Ross - Computer Networking_ A Top-Down Approach

In the book, the author asserts that,

Throughout a session, the FTP server must maintain state about the user. In particular, the server must associate the control connection with a specific user account, and the server must keep track of the user 's current directory as the user wanders about the remote directory tree. Keeping track of this state information for each ongoing user session significantly constrains the total number of sessions that FIP can maintain simultaneously. Recall that HTTP, on the other hand, is stateless-it does not have to keep track of any user state.

We also login into the websites, if HTTP is stateless (I don't exactly understand the meaning of the word), how does HTTP remember that user.

PS: I'm an EE undergrad, I don't know much about networking, so kindly bare with my naive doubt :)