What are Hooks in Drupal and can I learn and use them if I've yet to learn PHP? Whenever I try to read about what are Hooks in Drupal, and how to manipulate forms or content with them, the text seem not to deal with the UI at all, but mostly with coding... Maybe I did not encounter the right reading material about UI-Hook relationship?

Can someone please detail in simple words and  a simple example?


What are Hooks?
Do you use them via UI or only through Coding? 
Do I need to know PHP to use a module such as Hook form-alter?
Hooks can be thought of as internal Drupal events. They are also called callbacks, but because they are
  constructed by function-naming conventions and not by registering with a listener, they are not truly
  being called back. Hooks allow modules to “hook into” what is happening in the rest of Drupal.


Suppose a user logs into your Drupal web site. At the time the user logs in, Drupal fires hook_user_login. 

That means that any function named according to the convention module name plus hook name will be called. For example, comment_user_login() in the comment module,
locale_user_login() in the locale module, node_user_login() in the node module, and any other
similarly named functions will be called. 

If you were to write a custom module called spammy.module and
include a function called spammy_user_login() that sent an e-mail to the user, your function would be
called too, and the hapless user would receive an unsolicited e-mail at every login.


  The most common way to tap into Drupal’s core functionality is through the implementation of
  hooks in modules.


You have to use coding to implement hooks and you need to know PHP. 


  For more details about the hooks Drupal supports, see the online documentation at
  http://api.drupal.org/api/7, and look under Components of Drupal, then “Module system (Drupal hooks).”