The Mysterious Island has many themes, but three in particular stand out. The most conspicuous theme is the power of human ingenuity. This point cannot be missed. The full power of the creative powers of the colonists, particularly Cyrus Harding, is on display. From very little they create a telegraph, elevator, and so much more. It is the theme of subduing nature. Science and engineering save the day.

Another theme that is interwoven into the story is the importance of teamwork. Everyone works together. In fact, this teamwork is what allows the colonists to survive and even thrive on Lincoln Island. There is a vivid illustration of this point. When the colonists find Ayrton, he looks insane. He is the opposite of the colonists. Harding makes an astute observation:

“It is a great misfortune to be alone, my friends; and it must be believed that solitude can quickly destroy reason.”

Here is the point: without each other and teamwork, the colonists would be the same way.

Finally, there is the theme of goodness. Why does Captain Nemo save and help the colonists? He does so because he believes that they are good people. He is right; the goodness of all the men shine in the novel.