title: Salesforce Session variables, set and get variables in Session
body: <p>I want to be able to read / write some variables to the current session in my Salesforce site pages.</p>
  
  <p>I have a site built using Salesforce Sites, I need to store/retrieve some values across all the pages (consider that I am building something similar to a shopping cart).
  However I cant find any good example on how to read and write variables to the session (anonymous user).</p>
  
  <p>I am using Visualforce pages with several controllers built in Apex.</p>
  
  <p>Regards</p>