Having only one source of income is an outdated approach to personal finance. Side Hustle shows you how to develop solid business ideas, choose the best concept, run preliminary numbers and tests, and scale your business. Side Hustle is the guide to turning your ideas into successful, sustainable income and personal pride. The difference between a hobby and a side hustle is income, and Guillebeau provides a step-by-step guide to making your side hustle something that supports you, not the other way around.