One hundred and seventy-five years ago, a Swiss immigrant took America by storm, launching American science as we know it. The irrepressible Louis Agassiz, legendary at a young age for his work on mountain glaciers, focused his prodigious energies on the fauna of the New World. Invited to deliver a series of lectures in Boston, he never left, becoming the most famous scientist of his time. A pioneer in field research and an obsessive collector, Agassiz enlisted the American public in a vast campaign to send him natural specimens, dead or alive, for his ingeniously conceived museum of comparative zoology. As an educator of enduring impact, he trained a generation of American scientists and science teachers, men and women alike. Irmscher sheds new light on Agassiz’s fascinating partnership with his brilliant wife, Elizabeth Cary Agassiz, a science writer in her own right who would go on to become the first president of Radcliffe College.