Herbert Spencer (1820–1903) was an English philosopher, biologist, anthropologist, and a leading figure in the intellectual circle of Victorian England. Widely regarded as one of the principal contributors to the field of sociology, he was an advocate of the theory of social Darwinism. His works reflected a comprehensive approach which sought to apply evolutionary theory to various aspects of society including ethics, politics, and psychology. Spencer coined the phrase 'survival of the fittest,' which he expounded in his collection 'Essays: Scientific, Political, and Speculative' (1858, 1863, 1891). This collection encapsulates his views by exploring a diverse assortment of topics from education to political ideology. A prolific writer, Spencer's notable works include 'The Principles of Psychology' (1855), which aimed at reconciling the science of psychology with philosophical analysis, and 'The Principles of Sociology' (1876), where he provided an extensive analysis of social institutions and their evolutionary progression. Spencer's literary style was marked by the application of rationalism and positivism, often advocating for a laissez-faire approach to socio-political issues. Despite criticism and fluctuating popularity over the years, Spencer's contributions to the 19th-century intellectual landscape remain significant, and his works continue to be referenced in the discourse on social theory and philosophy.