That book needs to be read with a bucket of salt.
The problem is that it mixes things that are purely individual style, issues that are definite bugs, and everything in between, and does not distinguish between them in the text/
For example, the author of the book favors K&R brace style. Fair enough that is his view, but not mine. I respectfully disagree. Also the author recommends me to write Some::Module::Name->new() not Some::Module::Name::new() because the latter form will cause bugs if Some::Module::Name is a subclass of another module, and does not define a constructor.
The problem is that style issues and real bug avoidance are mixed together without much in the way of distinction and labeling. Each bit of advice comes with a few paragraphs of argument, and if you read those paragraphs you can usually (but not always) deduce which suggestions are just style and which are important, but I would hate for the book to fall into the hands of manager who does not know perl and blindly dictates that the whole book will become the company coding standard.