Boolean variables can be used as switches. They basically have 2 states: True and False (or "On and Off" or "1 and 0").
A Boolean variable uses the least memory compared to other variable types. The reason for this is a Boolean value can only be 1 or 0. Whereas, compared to an Integer Value, which can be anything from −32,768 to 32,767 (I believe). For this reason, it is recommended to use Boolean's where-ever possible.