The major conflict of Ernest Hemingway's "The Old Man and the Sea" is certainly man against nature. Santiago is experiencing an inner conflict because he desperately needs money and is afraid he is getting too old to continue fishing for marlin by himself. However, this inner conflict only contributes to the major conflict by providing and explaining his motivation. The fight with the great fish is only part of the conflict of man against nature. Santiago also has to fight with the sharks that are devouring his prize after he has succeeded in capturing it and tying it to his small boat. It would seem that a lone man, and an old one at that, is fighting the entire sea itself.
Santiago is defeated, but he puts up an admirable fight, in the tradition of Hemingway's heroes. Hemingway lived in Cuba for many years and was an avid fisherman. He liked to write in the mornings and then go out in his boat the Pilar in the afternoons. He was getting old himself when he wrote "The Old Man and the Sea," and, like Santiago, he was suffering from doubts about himself. The long story has been read as an allegory in which Santiago represents Hemingway himself, the marlin represents the literary work he needs to create in order to prove to himself and to the world that he still has the capability to produce top-quality literature--and the sharks have been thought to represent Hemingway's critics or his literary competitors who would like to see him toppled from his position as America's number-one fiction writer.
"The Old Man and the Sea" was a great critical and financial success. Life magazine devoted an entire issue to publishing the entire work, complete with an array of photographs, an unprecedented honor. The book was extremely helpful in getting Hemingway awarded the Nobel Prize for Literature in 1954. It was made into a successful motion picture in 1958.