Equity financing for entrepreneurial firms has attracted increasing attention in both the popular press and academic literature. The dramatic growth in the venture capital industry in past two decades has been accompanied by new academic research that explores its form and function. Angel financing, while less well-understood, is also attracting attention. At the same time, many of the questions that are most critical to policy-makers remain unanswered. Thus, this chapter has a twofold role: to summarize and synthesize what we do know about equity finance from recent research, and to indicate the important questions that we cannot yet answer.