Aristotle's treatise De anima examines the nature of the soul. However, 'soul' here should not be understood as the subjective center of our mental life, but rather as the principle that distinguishes living bodies from inanimate ones. It encompasses all forms of life, including plant, animal, and human life. The aim of the work is to define the soul, that is, to explain what it means for these forms of life to be alive. It discusses vegetative self-preservation, perception, human thought, and the locomotion of living beings. De anima is one of Aristotle's most fascinating and philosophically rewarding, yet also more challenging writings. The bilingual study edition offers a complete new translation, using the edition of the Greek text by Aurelius Förster.