Modernist Laboratories examines the nexus of science, literature, and discourses of progress in Spanish American literature from 1870 to 1920. Across the book's chapters, María del Pilar Blanco dives into the space of the periodical as a testing ground for the emergence of new writing forms across Spanish American spaces--forms that, in turn, express distinct definitions of, and desires for, progress. She looks to long- and short-lived periodicals from different locations in Spanish America: among them, Santiago Sierra's El Mundo Científico (published in Mexico between 1877 and 1878), Enrique José Varona's Revista Cubana (1885-95), the Revista Moderna (de México) (1898-1903; 1903-11), La Ilustración Espírita, Mexico City's main spiritualist review, published throughout the 1870s to 1890s, and José Martí's children's magazine La Edad de Oro (1889). What Blanco calls a 'poetics of progress' reveals a panoply of realities and desires experienced by Spanish American writers and artists in the fin the siècle: the theorization of belonging (and non-belonging) within increasingly complex geopolitical contexts; the shaping of institutions and educational projects across nations; encounters with technological advancement, and social-scientific rationalizations of anti-imperialism. Each of these is a distinct formulation of progress that develops within the growing, accumulative, and experimental spaces of periodicals. Put differently, the lives of these ideas take shape within the polyphonic, often bristling spaces of journals, magazines, and newspapers. The product of extensive archival research, Modernist Laboratories studies the material and intellectual environments that are crucial to understanding where and how new forms of writing emerge during a transformative period in Spanish America, and how they, in turn, inform the development of literary modernism.