Thomas Harriot is one of the most unique personalities in the history of science. Polymorphic intellectual and scientist, he built his career in the service of influential English aristocrats with whom he shared the business and political vicissitudes of the Elizabethan era. Today he is an extensively studied author as well as the subject of specific conferences from which important contributions have emerged that have allowed us to frame and contextualize his work. There was, however, no work of synthesis that retraced his scientific production against the background of his patrons’ biographies. No studies highlighted how Harriot's patrons shaped his work. Harriot, for instance, served time in prison for his connection to Henry Piercy (ninth Earl of Northumberland) and Walter Raleigh, who were involved in the so-called Gunpowder Plot against the Protestant ruler James I. Like Harriot, Piercy was imprisoned, while Raleigh lost his life.

Robyn Arianrhod's book succeeds in filling this lacuna. She traces Harriot's career from his trip to North America as a mathematical expert following Walter Raleigh, to the discovery of new colonial routes, on which his single publication, A briefe and true report of the new found land of Virginia, is based. The travel report is an important contribution to ethnography and anthropology, because it was one of the first studies on the social and cultural organization of Native Americans.

Harriot worked on many themes—astronomy, optics, the theory of matter, algebra—at the center of the scientific renewal that took place in the seventeenth century. Yet none of his studies were published, and his work, albeit important, circulated only in narrow cultural circles—namely, the group of intellectuals that gravitated around the figure of Henry Piercy. Harriot's results and discoveries remained virtually unknown outside the international circuit animated by the works of Galileo, Kepler, Descartes, and Newton, around which the Scientific Revolution and a new vision of the world began. Although Harriot had anticipated, for instance, Galileo's astronomical observations with the telescope, his manuscripts circulated just among his disciples, who succeeded in posthumously publishing only a single treatise on algebra (Artis Analyticae Praxis) in 1631, leaving the bulk of his writings unpublished and unknown until fairly recent times. Harriot's first biography, by John William Shirley, was published in a limited edition in 1900, but released on a large scale only after the reprint of 1972. Only in the second half of the twentieth century did Harriot's work begin to be studied in depth and his right place in the history of science restored. His important role, for example, as a promoter of an atomistic theory of matter—an idea and a concept central to late seventeenth-century authors like Robert Boyle, Thomas Hobbes, and Newton—was finally recognized.

Arianrhod knows the primary sources very well and skillfully manages to make the complex themes developed by Harriot—from astronomy to algebra—accessible. The book, conceived for a wide-ranging public, does not fail in scientific rigor. It rests on a strong foundation of primary and secondary literature, listed in a rich, up-to-date bibliography, that makes an excellent introduction to Harriot's corpus. Visual aides also heighten the book's accessibility. Seventeen geometric schemes of the cosmos and planetary movements are reproduced in the appendix as well as the famous lunar map that anticipates the much more famous one published by Galileo in Sidereus Nuncius. Eight photographs also show some of the manuscripts with calculations of algebraic formalism, which Harriot adopted for geometry, optics, and interpolation. The book, divided into twenty-three chapters that also increase accessibility and understanding, is accompanied by an analytical index that lists personal names, topics, and themes, including current historiographic debates like Harriot's comparison with Galileo, Descartes, and Kepler.