Plutarch was not concerned with writing histories, as such, but in exploring the influence of character, good or bad, on the lives and destinies of famous men. The first pair of lives the Epaminondas-Scipio Africanus no longer exists, and many of the remaining lives are truncated, contain obvious lacunae and/or have been tampered with by later writers.

His Life of Alexander is one of the five surviving secondary or tertiary sources about Alexander the Great and it includes anecdotes and descriptions of incidents that appear in no other source. Likewise, his portrait of Numa Pompilius, an early Roman king, also contains unique information about the early Roman calendar.