A Detective Story
About Solving the Mystery
of Customer Behavior



A detective story for anyone looking to solve the mystery of who their customers really are, what they really want, why they leave, and how to bring them back.


Customers can be a mystery. Despite the availability of more data than ever before, everyone, from the CEO to salespeople in the field, still finds it challenging to understand who their customers really are, why they act as they do, and what they really want.

To solve this challenge, learn to think like a market detective.

David Scott Duncan shows you how in his instructive and entertaining story of Tazza, a fictional chain of cafes trying to go big time. The only problem: sales are declining, and its leaders can’t figure out why.

In response, they launch an investigation led by a cast of characters including Cate Forrest, Tazza’s CEO, Alex Baker, a self-described “Market Detective,” and Jordan Sims, a young computer whiz at Tazza. Together, they discover why even their most loyal customers walked out the door – and how they can get them back.

The key lesson of the Tazza story is a simple, powerful idea that upends how most businesses view their customers. Customers have “jobs to be done”. They “hire” companies to solve these jobs and “fire” them when unhappy. Through vivid characters and situations that people working in any kind of organization can relate to, The Secret Lives of Customers provides an innovative path and practical tools for solving whatever market mysteries you face.

“Prepare to be hooked! With style, humor, and a lighthearted parable, The Secret Lives of Customers will help you see your customers with fresh eyes… and keep you smiling, nodding, and eagerly turning the pages for more.”

author of the international bestseller

Broad audience: Everyone in an organization – including those working in executive leadership, marketing, innovation, product development, sales, customer service, and even departments such as HR or Finance – needs to think like a market detective so they can stay attuned to what customers want, today and in the future.

Shows how readers can be the “Sherlock Holmes” of their business – by asking the right questions, gathering clues, identifying patterns, and developing insights into how to truly improve their customers’ lives.

The COVID era, characterized by radical changes in the way people are living and in the way organizations are operating, makes understanding the changing priorities and circumstances of customers – and finding new ways to serve them – more important than ever.


“A fresh approach to understanding what customers really want, told through an entertaining detective story. This is essential reading for anyone looking to understand their customers, today and in the future.”

Karen S. Lynch

President and Chief Executive Officer at CVS Health

“A grand slam: an excellent detective story, with key lessons that are easy to grasp and rigorous. Learning to understand customers has never been so much fun—and so easy.”

Jacques Goulet

President at Sun Life Financial Canada

“A page turner that reads like a mystery but filled with practical insights for sleuthing out what your customers really want. With a cast of characters you’ll easily recognize, Duncan’s story is a blueprint anyone can use to solve the mysteries of customer behavior.”

Mark Bertolini

Chairman and Chief Executive Officer at Aetna

“The promise of the data and analytics revolution for improving customers’ lives can only be realized if it’s focused on asking—and answering—the right questions. Duncan provides a blueprint for how to do just this, and does so through an engaging, accessible story that everyone can relate to.”

Brian Cassin

Chief Executive Officer at Experian


David Scott Duncan is a managing director at Innosight, where he works with leaders to create customer-centric teams, strategies, and organizations.

He is the co-author of two previous books, including the Wall Street Journal bestseller Competing Against Luck: The Story of Innovation and Customer Choice, written by the late Harvard Business School professor Clayton Christensen. A leading authority on the theory and application of jobs to be done, Duncan has extensive experience conducting market investigations around the world. Prior to Innosight, he worked as a consultant at McKinsey & Company and earned a Ph.D. in physics from Harvard. He lives with his family in Rhode Island.

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