I get this inb the Python interpreter v. 2.3 >>> >>> X=99 >>> X is 99 True >>> Y=100 >>> Y is 100 False >>> Numbers less that 100 get True, more than 100 get False. It seems. What does this mean? If nothing, then why does it happen? I mean how do you explain 'is' or 'id(X)' to the first time programmer when it does this to you. Peter