The book Lambda —which is published here critically, explained, and translated— represents the culmination of the treatise Metaphysics, as in this work Aristotle provides us with knowledge regarding the divine first principle, from which, as he himself states, the heavens and nature depend.
After a long investigation into how we can arrive at the discovery of a necessary, eternal, and unchanging substance, Aristotle teaches us in the book Lambda what and how many of these divine substances are.
He leads us from the heavenly bodies, which are responsible for the orderly and ceaseless generation of perishable substances, to their souls, which are responsible for their eternal movements, and from the souls of the heavenly substances he guides us to the immovable eternal substances, that is, to the self-sufficient intellects, the first of which is the Good itself, the ultimate final cause and the beginning of the causal cosmic chain.
