What is the author's style in The Three Musketeers by Alexandre Dumas, pere?

Dumas's characters are vividly drawn and easily recognizable: d'Artagnan, with his youthful optimism, country-bumpkin naivete, and belief in his own self-worth; Athos, who is melancholy and carries a secret sorrow; Porthos, who is loud, grandiose, and flamboyant; and Aramis, who is somewhat effeminate and who longs to enter the Church. They are not "deep" characters, and the reader learns little about their inner feelings and motivations and even less of their pasts, but they are drawn vividly enough to become memorable people who remain in readers' minds and engage their interest.