"Positioning" is a book written to appeal to the then burgeoning "marketing professional" a job description that I do not believe was well separated from advertising as of yet. Therefore, "positioning" caters to people who are involved in the selling of products and services, but that do not necessarily have any formal training in psychology. Although some of the bases of the theory of perception and memory are inherent in the concept presented as "positioning", the theoretical underpinning are not explored at all, and the authors either do not know about them, or make no effort to demonstrate they do, which in a way undermines the effectiveness of the contents of the book. This happens because, due to the lack of any theoretical basis for the concepts the authors claim to be effective, the book becomes a series of anecdotes that have not withheld the passing of time very well. This would not matter if there was some theoretical backing for the arguments presented, but leaving the whole support of the ideas to anecdotes from "successful" companies that have (in most cases unconsciously) applied the concept of positioning makes the book very weak after 20 years.
"Positioning" also falls for the logical trap of presenting all ideas as directives, and then copping out by establishing that, if it doesn't work, it must be the marketing practitioner's fault. The last chapter mentions that "To be successful at positioning, you have to have the right mental attitude... This requires patience, courage, and strength of character". Therefore, if the "positioning" strategy fails, it is your fault, not the concepts. Also, the examples that are not success stories are presented ambiguously enough to leave unclear whether the "directions" should be followed or not, but there are enough straightforward instructions to make you feel like the concept is foolproof, and that any failures in applying the techniques marked as "winners" are through the marketing manager's fault, not that the concept might be incomplete. The book is not without merit, since it does approach the subject quite clearly and concisely, and does give an approximation to a concept that is well known and well researched by now.
It is a shame that an interesting subject and an interesting topic is presented in such an unrewarding and unchallenging manner.