For your own sanity don't look at Excels handling of Boolean values
Enter True or false in a cell Excel will treat it as a Boolean value, try the same thing via code and enter a whole world incorrect types. The source of this particular pain is the auto conversion of the cell to Boolean type and there being no way of specifying a cell is a Boolean value.
I caveat this with "That I have manged to find", "I quickly got bored and just used integers", "Life's to short for messing around with this", "Really FFS"