Login Shell Vs Non Login Shell

Now I start reading TLCL(The Linux Command Line), then I come across login shell and non-login shell.

A login shell session is one in which we are prompted for our username and password; when we start a virtual console session, for example.
A non-login shell session typically occurs when we launch a terminal session in the GUI.

The differences between them is that login shells read one or more startup files as shown below:

• /etc/profile
• ~/.bash_profile
• ~/.bash_login
• ~/.profile

Non-login shell sessions read the following startup files:

• /etc/bash.bashrc
• ~/.bashrc