The present work is the first ever English translation of the original text of Thomas Harriot's Artis Analyticae Praxis, first published in 1631 in Latin. Thomas Harriot's Praxis is an essential work in the history of algebra. Even though Harriot's contemporary, Viete, was among the first to use literal symbols to stand for known and unknown quantities, it was Harriott who took the crucial step of creating an entirely symbolic algebra. This allowed reasoning to be reduced to a quasi-mechanical manipulation of symbols. Although Harriot's algebra was still limited in scope (he insisted, for example, on strict homogeneity, so only terms of the same powers could be added or equated to one another), it is recognizably modern.

While Harriot's book was highly influential in the development of analysis in England before Newton, it has recently become clear that the posthumously published Praxis contains only an incomplete account of Harriot's achievement: his editor substantially rearranged the work before publishing it, and omitted sections that were apparently beyond comprehension, such as negative and complex roots of equations.

The commentary included with this translation attempts to restore the Praxis to the state of Harrios draft. The authors based their work on manuscripts in the British Library, Pentworth House, and Lambeth Palace, and the commentary explores some of Harriot's most novel and advanced mathematics, very little of which has been published in the past. This publication will become an important contribution to the history of mathematics, and it will provide the basis for a reassessment of the development of algebra.

The present work is the first ever English translation of the original text of Thomas Harriot's Artis Analyticae Praxis, first published in 1631 in Latin. Thomas Harriot's Praxis is an essential work in the history of algebra. Even though Harriot's contemporary, Viete, was amongthe first to use literal symbols to stand for known and unknown quantities, it was Harriott who took the crucial step of creating an entirely symbolic algebra. This allowed reasoning to be reduced to a quasi-mechanical manipulation of symbols. Although Harriot's algebra was still limited in scope (he insisted, for example, on strict homogeneity, so only terms of the same powers could be added or equated to one another), it is recognizably modern.

While Harriot's book was highly influential in the development of analysis in England before Newton, it has recently become clear that the posthumously published Praxis contains only an incomplete account of Harriot's achievement: his editor substantially rearranged the work before publishing it, and omitted sections that were apparently beyond comprehension, such as negative and complex roots of equations.

The commentary included with this translation relates the contents of the Praxis to the corresponding pages in his manuscript papers, which enables much of Harriot's most novel and advanced mathematics to be explored. This publication will become an important contribution to the history of mathematics, and it will provide the basis for a reassessment of the development of algebra.

Zusammenfassung
The Artis analyticae praxis was published in 1631 in Latin. Until relatively - cently, an English edition would not have been considered necessary since most of the people who might have been expected to be interested in the text would have been able to read it in Latin. That is no longer the case and it is ?tting that an English edition should be published. It is also the case that a considerable proportion of the readership of the present volume will not be professional mathematicians, so we have tried to produce a translation that makes the mathematical content accessible to the modern reader. This is not because the algebra is intrinsically dif?cult but because it is not the kind of mathematics which is a part of today's secondary school curriculum. A further problem lies in the fact that the book in the form in which it was - blished in 1631 may very well not conform to Harriot's intentions for the publi- tion of his mathematical manuscript papers. This is why the book is accompanied by a Commentary which attempts to compare it with the appropriate passages in the surviving manuscript papers. The present work is a translation of the original text and not intended as a facsimile. The original has well over 300 errors (there may very well be more) and we have listed these at the end. In the interests of mathematical accessibility we have tried to produce a mathematically clean copy.

Inhalt
The Practice of the Analytic Art (translation).- Preface to Analysts.- Definitions.- Section One.- Section Two.- Section Three.- Section Four.- Section Five.- Section Six.- Numerical Exegesis.- Rules for Guidance.- Commentary.- Comparative Table of Equations Solved.- Textual Emendations.