Letters on the Laws of Man's Nature and Development (1851) is a published compilation of letters between Harriet Martineau (1802-1876), a nineteenth-century intellectual, feminist, and writer, and Henry George Atkinson (1818-1884), a philosopher and writer. The correspondence was initiated by Martineau, requesting Atkinson's expertise on matters about humankind's meaning, purpose, and role in the world. Martineau's central interest was to explore these questions beyond the boundaries of metaphysics and religion, thus ascertaining answers based on objective, scientific laws. Although Atkinson was not a scientist in the sense that we would today apply the term, he did engage intensely with some of the most popular pseudoscience of the day, such as phrenology and mesmerism (MacDonald 2019, 126). The enduring value of Letters as part of nineteenthcentury literary history is how it both reflected and shaped evolving Victorian ideologies on matters of religion and material science.