Essence and Form. The presence of Aristotle in Hegel’s «Wesenslogik» The aim of this research is to prove the relationship between the Hegelian concept of «Wesen» and Aristotle’s «ti en einai» from a not merely lexical point of view. I will specially attempt the reading of some fundamental moments of the Science of logic using the Lectures on the history of philosophy that Hegel dedicates to the Stagirite. Both signifiers, Wesen and ti en einai, refer to a sense of past, but timelessly past (zeitlos), which is pregnantly speculative. Hegel structures the division of the Objective Logic in two books, “Being” and “Essence”, on the model of the Aristotelian episteme. True science, meaning the one that goes deeply, looks beyond Being (to on) and, once found its Essence (ti en einai), puts this last one as its object. The logical journey from Being to Essence thinks highly this truth. I am convinced that founding such a relationship between the above-mentioned terms has a twofold contribution: On the one hand, which one of clarifying some key-moments of the Doctrine of Essence, so disambiguating expressions, or “formulas” that the Stagirite frequently uses as synonyms (i.e. essence, act, purpose and form); On the other hand, which one of reading, and correctly understanding, the past tense en in the middle of the Aristotelian formula; a past tense definitely metaphysical, which refers to what is necessary, unchangeable, out of time just because it is what time needs most of all and what legitimates time. The dissertation articulates into four chapters, corresponding to four distinct moments of investigation: Chapter I starts with some methodological remarks, and then provides my first general interpretation of the Hegelian Essence as dynamis. I will found this kind of reading on the Aristotelian concepts of essence, act and purpose. The analysis focuses on Aristotle’s Metaphysics and approaches a germinal connection between Wesen, An-sich, ousia, dynamis. Chapter II concerns the recollection (sich erinnert) of Being in Essence, that is, switching to a different level of logical argumentation, its connection on one side with Platonic anamnesis, on the other one with the Aristotelian ti en einai. Both anà and en refer to a past that is not truly such: it has no-time significance but clearly a logical-metaphysical one. Logical development is not made up of continuity but rather of breaks and always-new demotions; it recalls some famous words Socrates says to Meno: “And isn’t finding knowledge within oneself recollection?” (Meno, 85e-86a). Chapter III, in a direct link with the previous ones, thematizes the role of Reflexion as that immanent process of Essence, rethinking the complex balance of Being and Essence as, respectively, proteron pros hemas and proteron te physei, in turn corresponding to the Aristotelian formulas ti esti and ti en einai. Chapter IV, which takes crosswise the themes of the previous chapters, deals with the problem of Wirklichkeit at the end of the Doctrine of Essence, interpreting it in its twofold meaning of energeia and entelecheia. Despite Hegel, in his Lectures on the history of philosophy, apparently considers entelecheia as the most proper determination of energeia, he actually reveals two distinct senses, which correspond to different ranges of use. Wirklichkeit is then determined both as effectuality and as the determinacy of purpose. If, on the one hand, Hegel accomplishes a great ontological building, on the other hand he grounds an effectual reality that is only possible, still to submit to the scrutiny of the Subject, Concept, and Idea.