Boolean variables are stored as 16-bit (2-byte) numbers, but they can only be True or False. Boolean variables display as either True or False (when Print is used) or #TRUE# or #FALSE# (when Write # is used). Use the keywords True and False to assign one of the two states to Boolean variables.
When other numeric types are converted to Boolean values, 0 becomes False and all other values become True. When Boolean values are converted to other data types, False becomes 0 and True becomes -1.