Mathematics Outreach: Examples and Impact From Across the Globe focuses on mathematics outreach, which involves people sharing their passion for and knowledge of mathematics with the goal of broadening access to and engagement in mathematics learning experiences. Chapters contain rich descriptions and examples of mathematics outreach, together with reports of impact and effectiveness. Examples come from Ireland, the Philippines, Singapore, South Korea, and the United States. Authors describe outreach that engages people in a variety of mathematical experiences such as math circles, museum activities, mathematics festivals, problem-based puzzle environments, and math walks in the community.All chapter authors report on parameters of their mathematics outreach, including duration of activities, funding, facilitating the activities, and sustaining the outreach over time. Authors of two chapters describe surveys of the literature about mathematics outreach. We expect Mathematics Outreach may be of value to readers interested in developing and considering the impact of mathematics outreach in their own contexts.