Euh, sure this works: (Number readFrom: 'FF' base: 16) printStringBase: 2

Yes, one has to use "Number" instead of Integer and #readFrom:base: #readFrom: works too if you already have the string in source base representation, e.g. '16rFF'. The timing is good - currently work on the literal section for the new Pharo help system and will integrate this as an example in the tutorial. Bye T.