At the beginning of this work, Plutarch explains to his readers the reasoning and philosophy behind his "Parallel Lives." He will not recount each of the famous deeds in detail but will speak briefly, for he does not write history but lives. He wants to provide insights into the soul of Alexander (and Caesar), to psychograph them, and to talk about their lives and their characters.

Beginning with the sketch of Alexander, he speaks of his lineage, which traces back to Heracles, the ancestor of the Macedonians, as well as the rumor that he was the son of Zeus. His natural parents were Philip, king of the Macedonians, and Olympias, from the royal family of the Molossians of Epirus, a dynamic woman and a initiate of the Orphic mysteries.

His childhood was spent in Pella, Macedonia, with all the care of his parents for proper upbringing and education alongside the great sages of his time, the most important being the Stagirite philosopher Aristotle. His external appearance indicated a warm and feverish temperament; prudent yet simultaneously impetuous, decisive, and violent.