This is a definitive study of a major intellectual movement of nineteenth-century Spain. The 'harmonic rationalism' of the German Karl Christian Friedrich Krause (1781-1832), a philosophy dedicated to an ideal of universal brotherhood, had an unexpectedly powerful influence upon Spanish history, politics, education and literature in the late nineteenth century and beyond. Concerned primarily with the phase in which this all-embracing movement appears most homogeneous - between the revolution of 1854 and the early days of the Restoration - Professor Lopez-Morillas clearly outlines the Krausist doctrine and its relevance to Spain, particularly in the contexts of attitudes towards Germany and France. Because of the failure of the Enlightenment to establish any real roots in Spain and the political repression that delayed and weakened the Romantic revolt, the Spanish intellectual and political climate of the time was receptive to a philosophy that combined rationalism and idealism with social reform.