First of all, the book is by Mr. Giddins, not Mr. Higgins.
Secondly, although there is some material in the book which goes beyond what's happening in the opening, it's there because it's relevant to what's happening in the opening in question.
And finally, it's very silly to say that some of the stuff "doesn't qualify as opening stuff, tactics or anything else for that matter" because it must qualify as something. It might not be anything good, but if it's there then it qualifies as something!
Please try to be more careful and thoughtful in your reviews. Thanks.