Mr. Underhill and his company are pioneers in studying the retail environment in a methodical and 'scientific' way. The whole methodology depends on observation, thorough observation; which is later subjected to analysis and from that analysis they come up with valuable conclusions and suggestions for their clients.
The book does, however, contain parts in which Mr. Underhill wanders off his area of expertise and starts projecting into the future without solid basis; thereby losing some credibility. It also seems that Mr. Underhill is not well versed on Marketing and I quote from Page 206, "But since the

early '80s, PoP has really become a player, & now commands a seat at the selling table right next to marketing's", Any apprentice of marketing knows that PoP (point of purchase) is one of the many sales promotional tools that are only one part of Marketing Communications which is but one of 6 main categories of tools at the marketer's disposal. In actuality, PoP does in fact have a chair on the Marketing Table along with many other tools, such as the internet.
I think Mr. Underhill shares a common misconception held by many non-marketers that marketing = advertising; while in fact advertising is still only a tool and only part of Marketing communications just like Sales Promotion and Merchandising.

The book is full of useful and insightful retail information. The essence of the book is how to keep the customer in the store longer, at a greater level of comfort and easy navigation. Mr. Underhill is backed with years of observation and study of how a shopper interacts with the retail environment; an essential read for anyone in retailing and FMCG brand management. A great reference book