Twenty Thousand Leagues under the Sea is a widely influential 1869 novel by Jules Verne, and helped to create the science-fiction genre.
In the novel, international shipping lanes are threatened by a mysterious underwater monster that is sinking ships. Pierre Aronnax, a Natural History professor in Paris, theorizes that an enormous mutation of the common Narwhal -- a normally small whale with long tusks -- is responsible. Aronnax resolves to discover the truth, and is invited to join an expedition to find and destroy the monster.
I felt that my true vocation, the sole end of my life, was to chase this disturbing monster and purge it from the world.
"Besides," thought I, "all roads lead back to Europe; and the unicorn may be amiable enough to hurry me towards the coast of France. This worthy animal may allow itself to be caught in the seas of Europe (for my particular benefit), and I will not bring back less than half a yard of his ivory halberd to the Museum of Natural History." But in the meanwhile I must seek this narwhal in the North Pacific Ocean, which, to return to France, was taking the road to the antipodes.
(Verne, Twenty Thousand Leagues under the Sea, eNotes eText)
Aronnax joins the expedition not as a primary actor, but as a scientific observer; he is willing to leave the military and oceanic activities to their qualified men, but wants to have the academic glory of discovering and presenting a new species of narwhal to the world. His plan is simple: ride on the ship that kills the beast, and then use his scientific credentials to study, identify, and document its nature; this will allow him both academic prestige and personal vindication of his theory, which had been scorned by mainstream science. Of course, he does not find a narwhal, but a nuclear submarine, decades before its real-life invention.