Finally, a worthy title, a worthy edition and binding, and worthy translation of the forgotten paper that transformed the world of finance long after its genius author had passed from this mortal coil. Louis Bachelier's "The Theory of Speculation" was previously only available in French (online at NUMDAM, under Théorie de la spéculation. Annales scientifiques de l'École Normale Supérieure) and in English in the obscure 1971 book "The Random Character of the Stock Market" edited by MIT's Paul Cootner.
Davis and Etheridge's commentary and background and helpful timeline are all welcome, but a thorough biography of Bachelier and his sad life remains to be written. The index is adequate for such a slender volume.