[The] universe Lee helped bring into being is the one filled with the utterly fantastic, yet very human characters of Marvel superhero-dom.

Like the Amazing Spider-Man, web-slinging crimefighter with a problem. The Incredible Hulk, rampaging green Hyde to a meek scientist's Dr. Jekyll. The Silver Surfer, lyrical space rider trapped on the mad mudball that is Planet Earth. And Dr. Strange, magician and mystic fighting other-dimensional menaces….

Marvel characters change. They age, graduate from school, marry, divorce, have kids. Sometimes, they die. Always they remain fallible and human, whether or not they can send out optic beams, read minds, climb walls or whip up storms. Though other comic book companies use this approach today, Lee takes credit for starting the trend toward relevance and realism.

Another part of the Marvel style has been Lee's characteristic satiric sense—a good-natured, naturally humorous bent that expresses itself both in sharp...