Socrates, as depicted by his devoted student, Plato, is one of the true spiritual giants of recorded history, standing in such company as Jesus and the Buddha. The Phaedo preserves the moment where Socrates earned his immortality, forced to commit suicide by the Athenian democracy.

Plato's Phaedo, also known to ancient readers as Plato's On The Soul, is one of the great dialogues of his middle period. The Phaedo, which depicts the death of Socrates, is also Plato's fourth and last dialogue to detail the philosopher's final days, following Euthyphro, Apology, and Crito. In the dialogue, Socrates discusses the nature of the afterlife on his last day before being executed by drinking hemlock. One of the main themes in the Phaedo is the idea that the soul is immortal.

Plato was a philosopher, as well as mathematician, in Classical Greece. He is considered an essential figure in the development of philosophy, especially the Western tradition, and he founded the Academy in Athens, the first institution of higher learning in the Western world. Along with his teacher Socrates and his most famous student, Aristotle, Plato laid the foundations of Western philosophy and science. Alfred North Whitehead once noted: "the safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato."