If you tell too much too soon, you’ll overload them and they’ll give up. If you confuse them, they’ll ignore the message altogether.”  – Paco Underhill, Author 


Book Data

Publication Date: 1999

Print Length: 384 pages 

Best Sellers Rank:

#10 in Market Research Business (Amazon Books) 

 #40 in Marketing and Consumer Behavior (Amazon)  

 #68 in Cultural Anthropology (Amazon Books)  

The Topic

In “Why We Buy,” retail consultant Paco Underhill explores the behavior of shoppers.  Specifically, Underhill focuses on the science and psychology behind retail shopping. He delves into the behaviors, habits, and preferences of consumers to provide insights on why people buy certain products over others. The book offers valuable tips for retailers on optimizing store layouts, product placements, and overall shopping environments to improve customer satisfaction and increase sales. It is aimed at helping business owners, marketers, and retail designers better understand their customers in order to succeed in a competitive marketplace.

The Ideal Reader

Paco Underhill wrote “Why We Buy: The Science of Shopping” primarily for business owners, retail managers, marketers, and retail designers. By understanding how customers behave in a retail environment—from how they move through the store to what captures their attention—retail professionals can optimize store layouts, product placements, and marketing strategies to increase sales and improve customer satisfaction. The book is also of interest to anyone curious about the underlying factors that influence our shopping habits.

Retail Business Owners: As the decision-makers for store layouts, staffing, and marketing strategies, understanding consumer behavior can directly impact the bottom line. The insights from “Why We Buy” can guide them in making data-driven decisions for optimizing sales and customer experience.

Store Managers: Those who manage the day-to-day operations of retail stores benefit from understanding the nuances of customer behavior. Knowing, for example, why certain displays attract more attention can help them implement effective in-store promotions.

Marketing Professionals: Marketers who specialize in retail can use the book’s insights to craft more effective advertising and promotional campaigns targeted at driving in-store visits and purchases.

Retail Designers: These professionals are responsible for the store layout and the design of retail spaces. Understanding the psychology of shopping can help them design spaces that are not just visually appealing but also functional in guiding customer behavior.

Consumer Behavior Researchers: Academics and researchers focusing on consumer psychology can find real-world applications of theories they study.

Curious Shoppers: Even everyday consumers interested in understanding their own behavior can gain insights that might make them more informed shoppers.

The Promise

Paco Underhill’s implicit promise to the readers of “Why We Buy: The Science of Shopping” is to provide a deep understanding of the psychology and behavior of shoppers. Through this understanding, retailers and business professionals are better equipped to make informed decisions that will optimize their stores for increased sales and improved customer satisfaction. The book aims to turn observational data into actionable insights, offering strategies to influence customer behavior. For the general reader or consumer, the promise is an eye-opening look into why they shop the way they do, potentially informing their future shopping decisions.

The Title

The title “Why We Buy” is simple, direct, and instantly intriguing, prompting potential readers to consider the motivations behind their own purchasing behaviors. It appeals to a broad audience, from business owners and marketers to the general public, because the act of buying is something everyone can relate to.

The subtitle “The Science of Shopping” adds another layer of intrigue by suggesting that there’s a systematic study or methodology behind something as everyday as shopping. It lends the book an academic or expert tone, which can attract professionals and academics interested in consumer behavior, psychology, and business strategy.

Together, the title and subtitle encapsulate the book’s central premise: to dissect the act of shopping using a scientific approach to understand why people make certain purchasing choices. This balance of curiosity and academic rigor makes the title and subtitle highly effective in attracting a wide array of readers.

The Methodology

Underhill and his team at Envirosell, his consulting firm, conducted thousands of hours of field research, tracking customer movements, behavior, and interactions within stores. They analyzed various elements like store layout, product placement, signage, and even seemingly trivial details like the angle at which a product is displayed.

This hands-on, observational method allowed Underhill to gather real-world data, which he then translated into actionable insights for his readers. 

The Structure


Overview of what the book aims to achieve and who it is for.

The Science of Shopping

Explanation of Underhill’s methodology and the importance of understanding consumer behavior.

The Mechanics of Shopping

How consumers physically move through a store.

Discussion on store layout and its impact on shopping habits.

The Demographics of Shopping

Exploration of how different age groups, genders, and other demographics affect shopping behavior.

What Retailers Don’t Know

Common pitfalls and misunderstandings among retailers.

Strategies that don’t work and why.

The Dynamics of Store Design

Importance of store layout, lighting, and other design factors.

How these elements can either enhance or detract from the shopping experience.

Online vs. In-Store Shopping

A comparison of online and physical retail spaces and their respective consumer behaviors.

Signage and Promotions

The role of signs, advertisements, and promotions inside the store.

How effective signage can direct customer flow and influence purchases.

Sensory Experiences and Shopping

The influence of sensory factors like smell, sound, and touch on consumer choices.

The Future of Shopping

Predictions and suggestions for how retailers can adapt to future changes in consumer behavior.


Summarizing the key takeaways and their implications for retailers and marketers.

Chapter Structure

Introduction to the Topic

Brief overview of what the science of shopping entails.

The Importance of Understanding Consumer Behavior

Explanation of why this topic is critical for retailers, marketers, and even consumers.

The Author’s Expertise and Methodology

Introduction to Paco Underhill’s background and the research methods he employs, such as observational studies and data analysis.

Scope of the Book

What the reader can expect to learn from the book, outlining the range of topics that will be covered in subsequent chapters.

The Relevance to Various Audiences

Why the book is important for different reader demographics like business owners, marketers, and the general public.

This introductory chapter aims to establish the framework for the book, providing the reader with a clear understanding of what to expect and why the subject matter is important. It’s designed to draw the reader into the larger exploration of consumer behavior and retail strategy that the book offers.

What Made "Why We Buy" a Best Seller?

The book “Why We Buy: The Science of Shopping” became a bestseller for several reasons:

Universal Relevance: The topic of shopping and consumer behavior is universally relatable, appealing to both business professionals and the general public.

Expert Authority: Paco Underhill is an established expert in retail consulting and consumer behavior, lending credibility to the insights presented in the book.

Practical Application: The book offers actionable advice for improving retail strategies, making it a must-read for business owners, marketers, and retail designers.

Timely Research: The book encapsulated ongoing changes in retail and consumer behavior, making it highly relevant at the time of its release and maintaining its relevance as shopping environments continue to evolve.

Accessible Writing: The book is written in an engaging and accessible style, making complex psychological and business concepts understandable to a broad audience.

Case Studies and Real-world Examples: Underhill includes various case studies and real-world examples that help to illustrate the points he makes, allowing readers to see the practical implications of the theories presented.

Media Coverage: Favorable reviews and media coverage helped elevate the book’s profile, creating buzz that contributed to its bestseller status.

Word-of-Mouth and Professional Endorsements: Positive endorsements from notable figures in retail and business, as well as word-of-mouth recommendations, further boosted its popularity.

Educational Adoption: The book has been used in academic settings and professional training programs, extending its reach and longevity in the market.

Global Relevance: The insights in the book are applicable to various markets and cultures, adding to its widespread appeal.

The combination of an engaging topic, expert insights, practical advice, and timely relevance contributed to making “Why We Buy” a bestseller.

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