This report is a GEM Special Report on Senior Entrepreneurship 2017, sponsored by various institutions including London Business School, Babson College, Universidad del Desarrollo, Universiti Tun Abdul Razak, and Korea Enterprise Foundation. The authors, Thomas Schøtt, Edward Rogoff, Mike Herrington, and Penny Kew, express gratitude to the participating GEM national teams and the organizations that sponsored the work. The report uses GEM data, but its interpretation and use are the sole responsibility of the authors. The report acknowledges the contribution of the GERA data team and Rothko International for the design and layout of the report.