Craig Johnson & Brian Mullen 
The Psychology of Consumer Behavior [PDF ebook] 

After years of study in the area of consumer behavior, Mullen and Johnson bring together a broad survey of small answers to a big question: 'Why do consumers do what they do?’ This book provides an expansive, accessible presentation of current psychological theory and research as it illuminates fundamental issues regarding the psychology of consumer behavior. The authors hypothesize that an improved understanding of consumer behavior could be employed to more successfully influence consumers” use of products, goods, and services. At the same time, an improved understanding of consumer behavior might be used to serve as an advocate for consumers in their interactions in the marketplace.