The Transformation Book, which belongs to Pessoa's pre-heteronymic period, contains a series of fragments written in English, Portuguese, and French, none of which were ever published during Pessoa's lifetime. Conceived by Pessoa in 1908, a year of great social and cultural transformation in Portugal, The Transformation Book was designed to reflect and advance social and cultural transformation in Portugal and beyond. Moving between a number of literary forms, including poetry, fiction, and satire as well as essays on politics, philosophy, and psychiatry, The Transformation Book marks one of the fundamental stages in Pessoa's elaboration of a new conception of literary space, one that he came to express as a "drama in people." Alexander Search, Pantaleão, Jean Seul de Méluret, and Charles James Search are the four "pre-heteronyms" to which the texts of The Transformation Book are attributed. These four figures constitute a plural literary microcosm - a world that Pessoa makes, but that is occupied by a multiplicity of authors - and clearly anticipate the emergence of Pessoa's heteronyms. As the singular result of an intersection of Pessoa's personal intellectual trajectory with his hopes for fomenting cultural transformation, The Transformation Book makes for a unique contribution to Pessoa's ever-growing published oeuvre. Although some of the texts conceived as part of the Transformation Book have previously been published in isolation or as fragments, this is the first complete and critical edition of The Transformation Book, and most of the texts in this edition are published here for the first time. Through the critical efforts of Nuno Ribeiro and Cláudia Souza, a fundamental project of Fernando Pessoa's is now brought from the confines of the archive to the public in its most complete and accurate fashion. The Transformation Book should contribute to future studies on the work of one of the most distinctive geniuses of modernist literature.