This study examines how intellectual and institutional developments transformed the U.S. Navy from 1873 to 1898. The period was a dynamic quarter-century in which Americans witnessed their Navy evolve. Cultures of progress--clusters of ideas, beliefs, values, and practices pertaining to modern warfare and technology--guided the Navy's transformation. The agents of naval transformation embraced a progressive ideology. They viewed science, technology, and expertise as the best means to effect change in a world contorted by modernizing and globalizing trends. Within the Navy's progressive movement, two new cultures--Strategy and Mechanism--influenced the course of transformation. Although they shared progressive pedigrees, each culture embodied a distinctive vision for the Navy's future.