 Gómez Pereira only wrote three books: the Antoniana Margarita, published in 1554, an Apologia that he redacted in 1555 to answer the objections raised against his first book, and the Novae veraeque medicinae of 1558 (González Vila 1976: 111–114). As can be seen by the dates, the publication of his writings was concentrated in a few years, probably at the end of his life. It is, then, likely that these writings had many years of reflection, readings and experimentation probably determined by his profession. The Antoniana Margarita, entitled so in honor of Pereira’s parents, is his best-known work. It is composed in three parts without any internal division of chapters: the first part, which gives the title to the entire book, is the largest; the second is a commentary on Aristotle’s De anima III, and the third is a treatise De immortalitate animorum. The discourse is arranged in a sequence of paragraphs whose content is sometimes announced by marginal notes which are more numerous in the first part than in the other two. The prose is usually very dense and full of digressions, many of which are so extensive that they seriously break the thread of the main argument. The impression of disorder and lack of a previous expository plan is certainly overwhelming, so that only the interesting opening of the book, where Pereira introduces in media re the theme of animals’ lack of sensory perception, can attract the interest of the reader. In his Apologia, Pereira summarized and confirmed all the theses previously established in the Antoniana, and took the opportunity to clarify some points of his own thought, as for example the nature of human soul as a simple substance that only conceptually can be divided into parts. Finally, the Novae veraeque medicinae, probably published posthumously, were written following an empirical methodology that aimed to discover the true causes and the effects of diseases and affections. For example, against the common opinion of his time and the criteria of Greek and Arab medical treatises, Pereira explained fever as a mechanism devoted to restoring a lost equilibrium in the body.