This is the first book to offer a global study of Marsilio Ficino's philosophy since Kristeller's pioneering The Philosophy of Marsilio Ficino (1943). In seven chapters, Mariani Zini initiates us into Ficino's thought, unveiling progressively the various elements of her thesis through a detailed analysis of Ficino's most important works, in confrontation with Neoplatonic and medieval philosophers. According to her, Neoplatonism provides Ficino with a conceptual space in which to address in a creative way philosophical issues inherited from the ancient, patristic, and medieval traditions. Mariani Zini's leitmotif is that Ficino's philosophical choices are motivated by a need to place greater emphasis on the continuity and positivity of the procession of reality from God, rather than seeing it as a break, or a loss, from its perfect origin. Here Ficino rethinks the Neoplatonic doctrine of procession-conversion in order to solve its inherent contradiction—already partly identified by the Neoplatonists themselves—with the doctrine of creation ex nihilo: how can one conceive procession as a process that generates new beings rather than one that merely reveals beings that already exist?

To answer this question, Ficino transforms and adapts Neoplatonic doctrines to describe the causality between God and the world as a process that provides reality with what Mariani Zini calls an “increment of sense,” or even a renovatio. This philosophical optimism explains why Beauty is so central in Ficino (chapters 1–2): Beauty is not only the unfolding of the First Principle into all levels of reality (as in Proclus), but is the very power that generates, unifies, and allows multiplicity to return to God in a renewed, enriched, and beautiful way. It also explains why Ficino modifies significant elements of Proclus's ontology to provide a radically new doctrine of the soul: soul is no longer described as the middle between two levels of reality or the privileged access point to the intelligible world (as in Proclus), but is the very condition of possibility of the unfolding of unity into multiplicity, which in turn generates and structures new, heterogeneous unities at the inferior levels of reality (chapter 4). Ficino also reinterprets Neoplatonically the medieval concept of aliquid to describe how the soul, as the condition of possibility of multiplicity, alterity, and non-being, can represent to itself the different modalities of not-being (images, dreams, shadows) when they still consist of a “quasi something” (chapter 5). He proposes a new solution to the tension, central in Neoplatonic philosophy, between the soul's dependence on God and its autonomous capacity to generate multiplicity (chapter 6), and reelaborates the Neoplatonic doctrine of the ochēma to address the problem of the destiny of the soul after death and its cognitive function on earth (chapter 7).

In sum, this book convincingly presents Ficino as a coherent philosopher, characterized by an extraordinary understanding of the Neoplatonic tradition and an unlimited capacity to propose new, yet fundamentally Neoplatonic, solutions to important metaphysical problems. The author explains in detail in what way Ficino's philosophical choices justify his belief in the efficacy of theurgy, astrology, and demonology. She also underlines how limited Ficino's interest in Christian theological dogmas and apologetic topoi is in these discussions, as is his engagement with medieval reasoning: chapter 3 argues that Ficino's mode of reasoning in the Platonic Theology should not be dismissed just because it does not follow a rigorous method of deduction and demonstration. Ficino consciously moves away from such a method and develops instead a natural dialectic, which is intrinsically linked to a conception of religion as a natural and innate instinct shared by all humankind. In fact, Ficino's reasoning follows the conceptual method used by Proclus to explain various types of discourses according to their different function, and presents important affinities with Cicero's topics, a form of dialectical reasoning based on commonly held opinions rather than on demonstration. Ficino's aim, Mariani Zini argues, is to delimit what it is possible to believe rather than trying to deduce or demonstrate necessary theological or philosophical dogmas. Despite some flaws (numerous typographical errors and occasionally sloppy footnotes) and a few missed opportunities to link Ficino's thought to its immediate cultural context (particularly in chapters 3 and 7), this important book helps understand how Renaissance humanists radically changed philosophy.