Model-view-controller (MVC)

I wanted to review the MVC concept so I took a look back at Michael Hartl's Ruby on Rails Tutorial, specifically chapter 1.2.6. I particularly like the text and the picture for conveying the information. Reposting here for future reference.

When interacting with a Rails application, a browser sends a request, which is received by a web server and passed on to a Rails controller, which is in charge of what to do next. In some cases, the controller will immediately render a view, which is a template that gets converted to HTML and sent back to the browser. More commonly for dynamic sites, the controller interacts with a model, which is a Ruby object that represents an element of the site (such as a user) and is in charge of communicating with the database. After invoking the model, the controller then renders the view and returns the complete web page to the browser as HTML.