The Phaedo is acknowledged to be one of Plato's masterpieces, showing him both as a philosopher and as a dramatist at the height of his powers.
For its moving account of the execution of Socrates, the Phaedo ranks among the supreme literary achievements of antiquity. It is also a document crucial to the understanding of many ideas deeply ingrained in western culture, and provides one of the best introductions to Plato's thought.
One of the main themes in the Phaedo is the idea that the soul is immortal. In the dialogue, Socrates discusses the nature of the afterlife on his last day before being executed by drinking hemlock.
Socrates has been imprisoned and sentenced to death by an Athenian jury for not believing in the gods of the state (though some scholars think it was more for his support of "philosopher kings" as opposed to democracy) and for corrupting the youth of the city.
By engaging in dialectic with a group of Socrates' friends, including the two Thebans, Cebes and Simmias, Socrates explores various arguments for the soul's immortality in order to show that there is an afterlife in which the soul will dwell following death. Phaedo tells the story that following the discussion, he and the others were there to witness the death of Socrates.