-To determine whether to print an @notation{accidental}, LilyPond
-examines the pitches and the @notation{key signature}. The key
-signature only affects the @emph{printed} accidentals, not the
-note's @notation{pitch}! This is a feature that often causes
-confusion to newcomers, so let us explain it in more detail.
-
-LilyPond makes a clear distinction between musical content and
-layout. The alteration (@notation{flat}, @notation{natural sign} or
-@notation{sharp}) of a note is part of the pitch, and is therefore
-musical content. Whether an accidental (a @emph{printed} flat,
-natural or sharp sign) is printed in front of the corresponding
-note is a question of layout. Layout is something that follows
-rules, so accidentals are printed automatically according to those
-rules. The pitches in your music are works of art, so they will
-not be added automatically, and you must enter what you want to
-hear.
+LilyPond makes a distinction between musical content and
+its printed representation. Input such as @code{d4 e fis2}
+defines the pitches and durations of notes, which is musical
+content. The @notation{key signature} is part of the printed
+representation. The key signature also sets rules for the
+printed representations of notes. LilyPond compares each input
+pitch to the key signature to determine whether to print an
+@notation{accidental}.
+
+The command @code{\key} sets the @notation{key signature}, which
+affects the printed representation, but does @emph{not} change
+the pitch assigned to a note such as @code{c} in the input.