Phaedo is one of the dialogues written by the ancient Greek philosopher Plato. It is a philosophical exploration of the nature of the soul, the afterlife, and the concept of knowledge. The dialogue is set on the day of Socrates' execution, and it recounts the conversation between Socrates and his followers, including Phaedo, about his impending death and their beliefs about the soul.

Throughout the dialogue, Socrates argues that the soul is immortal and that the pursuit of knowledge is the key to achieving true wisdom. He uses a variety of analogies, including the idea of the soul being like a prisoner trapped in the body, to illustrate his points. Socrates also discusses the theory of Forms, which holds that there is a separate, ideal realm of existence that contains perfect and eternal Forms or Ideas, such as Beauty or Justice, that the physical world merely approximates.

Phaedo is considered one of Plato's most influential works, and it continues to be studied and debated by philosophers and scholars today. Its themes of the nature of the soul, the afterlife, and the pursuit of knowledge are central to many philosophical and religious traditions, and its exploration of these concepts continues to be relevant to contemporary discussions in ethics, epistemology, and metaphysics.