Insufficiency of research and theory on the relationship between entrepreneurship and grand challenges means that we know little about who engages and what repertoires of actions they take to tackle socioenvironmental challenges that transcend firms, markets, and nations, and what sorts of solutions they create. Drawing on the five articles featured in this symposium-and focusing especially on their protagonists or actors, the actions these actors take, and their achievements-we begin to conceptualize an impact entrepreneurship perspective. Following the tenet of e pluribus unum ("out of many, one") and adhering to the doctrine that diverse, decentralized human effort can improve the world, our impact entrepreneurship perspective refers to the development of solutions to grand challenges, in a financially, socially, and environmentally sustainable fashion. All in all, then, this symposium provides a starting point to discuss, conceptualize, study, interpret, and enrich our understanding of impact entrepreneurship and collective action to address grand challenges.Never doubt that a small group of thoughtful, committed citizens can change the world; indeed, it's the only thing that ever has. -Margaret Mead (quoted in Keys, 1982) This symposium considers how individuals, whom we collectively call entrepreneurs, resolve human-made socioenvironmental challenges that are so formidable and global that they transcend firms, communities, industries, governments, and nations. These challenges include pollution, poverty, resource inaccessibility, and injustice. Research, including this symposium, is predicated on the need to understand, attenuate, or, better yet, remedy the affronts of these grand challenges (Dean & McMullen, 2007;Markman, Russo, Lumpkin, Jennings, & Mair, 2016;York & Venkataraman, 2010). While a prevalent view is that either big governments or multinational corporations tackle such challenges-sometimes with financial support from endowments-this symposium offers a complementary view: that disparate individuals, groups, and small ventures can engage, contribute, and bring momentum to the effort needed to tackle grand challenges. Naturally, new developments in science, technology, politics, business, and public policy assist with novel ways of organizing and governing. However, our position is that scholarly research on modalities, especially of the entrepreneurial types, can extend ourThe authors express tremendous gratitude to general editor Phil Phan, an anonymous reviewer, Sophie Bacq,