Why We Buy by Paco Underhill (1999)

From the butt-bumping factor of tight store aisles to the social psychology behind the direction we head in when entering a store, this book is filled with fascinating and practical insights on the way people shop.Underhill writes with a chatty, conversational tone that make his books a delight to read.  Followed by The Call of the Mall, equally interesting but located over in the 300s.