Chris Guillebeau's book, Side Hustle, which is a guide for creating a profitable and fulfilling side hustle. The text walks readers through the process of developing a side hustle idea, starting with brainstorming ideas and validating them, transforming an idea into a viable offer, launching the offer to the public, and finally, growing and refining the hustle. The author provides numerous examples of side hustles and the strategies used by successful hustlers to earn money and achieve their goals.