The Apology of Socrates was written by Plato. In fact, it's a defensive speech of Socrates that he said in a court noted down by Plato.

The main subject of the speech is a problem of the evil. Socrates insists that neither death nor death sentence is evil. We shouldn't be afraid of the death because we don't know anything about it. Socrates proved that the death shouldn't be taken as the evil with the following dilemma: the death is either a peace or a transit from this life to the next. Both can't be called evil. Consequently, the death shouldn't be treated as evil.