As noted in the comments of the first (non-boldface) code example on the page, the
_ref variables should use dereferencing arrows to access values. Thus, the two
lines:

my $gap = $opts_ref{cols} - length $text;
my $left = $opts_ref{centred} ? int($gap/2) : 0;

should read instead:

my $gap = $opts_ref->{cols} - length $text;
my $left = $opts_ref->{centred} ? int($gap/2) : 0;

Shouldn't $tax_form be $tax_form_ref, especially this close to the Reference
Variables recommendation?

Function name is incorrect - it should be odd() (the function from the previous code snippet),
but the text refers to even() which DNE:

"... then a better solution is usually to "inline" the call to even(), replacing ..."

-Should Be-

"... then a better solution is usually to "inline" the call to odd(), replacing ..."

The example for Loop Labels does not seem to fulfill its intention, to 'give up trying to contact clients if any of their numbers is marked "Do Not Call"'.

The code as written gives up for a client only if the FIRST phone number in the client's list has a "Do Not Call". Otherwise, it uses that number as the preferred number to send an ad even if a subsequent phone number has a "Do Not Call". The "last PHONE_NUMBER;" statement ensures that subsequent phone numbers are not checked.

In the discussion of prototypes, the example code includes a subroutine called "clip_to_range"
that takes $min, $max, and @data as parameters. Based on that information, I expected the code
to return only those data elements that are between $min and $max.

Inspection of the code, however, revealed that through the use of List::Util's min and max
routines data elements that were less than $min were changed to $min and those greater than $max
were changed to $max. The code in question is map { max( $min, min( $max, $_ ) ) } @data.

For example, given $min = 1, $max = 3, and @data = ( 0 .. 4 ) I expected the subroutine to
return ( 1, 2, 3 ). It actually returns ( 1, 1, 2, 3, 3 ).

If this is the intended behavior of the subroutine, I suggest renaming it (as the use of "clip"
implies cutting and removing) and/or adding a comment that indicates that is the intended
behavior. If the code itself is in error, one simple fix might be something like grep { ($min <=
$_) && ($_ <= $max) } @data.

Replace
-onechar
with
-one_char

The last word, 'it', should have a footnote explaining that the unlinking process proposed does
not work under MS Windows, and that IO::InSitu should be used instead.

One of the most important paradigm shifts in this book is getting users to use
Class::Std module to build new perl modules (which ROCKS by the way). However,
Perl6::Export::Attrs is not compatible with Class::Std. This shoudl be pointed out in
the book. Or the modules need to be fixed.

(http://safari.oreilly.com/0596001738/9780596001735-CHP-19-SECT-14);
The code refactoring is mildly flawed because the original

$target_name = $1 and last

is not behaving the same way as the refactored

$target_name = $name;
last CANDIDATE;

for value "0", i.e. the candidate string is "Name: 0; "