This open access monograph presents the results of a study aimed at finding an answer to a perennial, yet notably topical, question in the philosophy of science, namely, “What is life?''  The authors contend that existing approaches to studying living systems fall short when it comes to understanding the phenomenon of life itself. The question of life, it is argued, is philosophical in nature, and hence outside the purview of science per se. This book proposes a novel mathematical framework that is carefully developed to meet the requirements of a general study of the phenomenon of life, revealing that the question already has an answer in a relatively recent development in pure mathematics, namely, hyperset theory. The authors leverage the results of the mathematicians' painstaking work over a few decades into their study. Their findings, when translated back to the realm of biology, rejoin, rather surprisingly, the Neoplatonic interpretive account of Plato’s natural philosophy. 
 
This book lies at the intersection of three major branches of knowledge: (i) philosophy, especially philosophy of life and philosophy of mind, (ii) mathematics, especially foundations of mathematics, and (iii) science, especially biology and physics; there is also some relevance to computer science and engineering. It is addressed to the scholars, researchers and graduate students in the area of philosophy of science, especially the field of philosophy of biology, with strong relevance to theoretical biology, mathematical biology, systems biology, philosophy of mind, and Neoplatonic philosophy of nature.