True and false

Any Scheme value can be used as a boolean value for the purpose of a conditional test. As explained in section , all values count as true in such a test except for and the empty list, which count as false. This report uses the word ``true'' to refer to any Scheme value that counts as true, and the word ``false'' to refer to any Scheme value that counts as false. true false

Bartley: tighten this up.