Envirosell, a global research and consultancy company based in New York, was founded and is led by Paco Underhill. He has been studying consumer behaviour for more than 25 years, making him a pioneer and top expert in the area. The 1999 book Why We Buy has been translated into 26 different languages and has sold more copies than any other retailing book in history. Three new chapters—one each on international markets, online shopping, and the most recent marketing strategies used by prosperous retailers—are included in this edition's updated and improved version.