The 'Variable List' presents the book's variables. Variable is composed of a name and it's initial value. You can Manipulate the Variables via the Variables panel in the Book tab, or via right clicking on the list which will pop a menu of actions.
There are two types of variables:
Switch - a switch's value can be 'on' or 'off'.
Numerical - a numerical variable can be any integer number from -100000 to 100000

Variable Toolbar
Add - Adds a variable to the list
Remove - Remove the selected variable from the list
Edit - Edits the selected variable from the list

Adding a variable
when the dialog shows up you must fill the
Type - You must choose whether the variable is a 'Switch' or a 'Numerical Variable' (this cannot be edited later)
Name - You must write a name for the variable. It is recommended the name to be descriptive for good organization, but it's not essential since a player will never see the variable name.
Value - If chosen switch, you will be given the option of 'on' or 'off. if chosen 'Numerical' you need to write down an integer number between -100000 to 100000

Displaying variable value
If you wish the present a variable value in the text of page you may use the following syntax: <#'Var_Number>.

will display the value of variable '1: Health' in place of the <#1>

Common Usages of a variable
Stats - tracing things such as 'Life' , 'Money' and the like is useful with a numerical variable
Events - tracing events which occurred over the story such as 'been there', 'done that' and the like is useful with a switch
Systems - with a little effort the usage of variables and Rule Paths can make an excellent battle system or any other system you'd like.