This document summarizes a book about how challenger brands can compete against brand leaders. It provides an overview of the book's contents and key ideas. The book discusses how challenger brands can adopt an "intelligent naivety" by questioning categories in new ways. It also advocates that challenger brands build a "lighthouse identity" where they project a strong sense of self and point of view to guide consumers, rather than just mirroring consumers' lives. The book outlines eight "credos" or principles for successful challenger brands, including taking thought leadership of categories and using communications to enter social culture.