This report covers seed and early-stage financing for high-growth companies in OECD and non-OECD countries with a primary focus on angel investment. Angel investment is the primary source of outside equity financing and support for start-ups in a number of countries, yet it is frequently overlooked as angel investors are often not visible. Following the recent financial crisis and continued difficult economic environment, angel investors have been playing an important role in filling financing gaps left by banks and venture capital firms. This report provides an in-depth look into angel investment, including definitions, data and processes. It reviews developments around the world and identifies some of the key success factors, challenges and recent trends. It then discusses policy measures for promoting angel investment, with examples from countries which have been active in this area. As part of the background research for this project, over 100 people were interviewed from 32 countries.