Pierre-Simon Laplace (1749-1827) is remembered amoung probabilitists today particularly for his "Theorie analytique des probabilites", published in 1812. The "Essai philosophique dur les probabilites" is his introduction for the second edition of this work. Here Laplace provided a popular exposition on his "Theorie". The "Essai", based on a lecture on probability given by Laplace in 1794, underwent sweeping changes, almost doubling in size, in the various editions published during Laplace's lifetime. Translations of various editions in different languages have apeared over the years. The only English translation of 1902 reads awkwardly today. This is a thorough and modern translation based on the recent re-issue, with its voluminous notes, of the fifth edition of 1826, with preface by Rene Thom and postscript by Bernard Bru. In the second part of the book, the reader is provided with an extensive commentary by the translator including valuable histographical and mathematical remarks and various proofs.

Published in 1831, this work forms part of a collection of introductory volumes suggested by Henry, Lord Brougham and Vaux, the Lord Chancellor, for the Society of the Diffusion of Useful Knowledge. Due to the exceptional mathematical ability of its author, however, it outgrew its original plan and has since been seen as a rather more ambitious project. Praised by Somerville's contemporary Sir John Herschel for its presentation of general astronomical theories and the mechanical principles employed in their derivation, the work was a tour de force of scientific and technical exposition. It is especially remarkable both for its author's firm grasp of the subject, especially given her lack of formal mathematical training, and for its clear outline of Newtonian philosophy for a popular audience.