Besides the study of capitalism and colonialism embodied in Robinson Crusoe, many researchers also conduct researches on the Providence and religion in the novel. When living on the island, Crusoe recognizes that he has been a sinner and converts himself into a Christian. The conversion has drawn many researchers’ attention. Martin (1966) describes the conversion as a symbolic voyage from sin and folly to the gift of God's grace attained through sincere belief in Jesus Christ. Orr (2014) further proposes that Crusoe's conversion is not from unbelief to salvation: he has always been a believer and a Christian since he never doubts the existence or omnipotence of Providence, but initially he does not demonstrate his belief through words and actions. 

However, although a lot of researches have been done to explore different aspects of Robinson Crusoe, few studies have touched upon the loneliness and solitude of Crusoe. Swados (1958) does propose that an examination of Robinson Crusoe may perhaps reveal to us the vaster problem of human loneliness. But Swados doesn’t conduct deeper analysis on Crusoe’s loneliness. Moreover, he fails to shed light on Crusoe’s solitude. Therefore, there is still a blank about the study of Crusoe’s loneliness and solitude. 

In terms of The Old Man and the Sea, many studies have been conducted to discuss the heroism of Santiago (e.g. Burhans, 1960; Debata, 2013; Morgan & Losada, 1992). Morgan and Losada (1992) present that Santiago exhibits three characteristics that are not only specific to, but also fundamental in, the definition of the Homeric hero. First, Homeric heroes are born to their destiny, which is correspondent with Santiago’s view that he is born to be a fisherman. Second, Homeric heroes are self-conscious and reflective, which means they can make their own choices. Similarly, Santiago has elected his own course of action. Third, basic to the identity of the Homeric heroes is that they are the “best”. Santiago is also the best as the boy insists that the best fisherman is Santiago. Besides, Debata (2013) also makes contribution to the study of heroism in The Old Man and the Sea. He states that Santiago is not the typical hero like Prometheus, Odysseus, Julia Caesar, Napoleon, who are esteemed and respected as models for heroes because they represent the collective desire and yearning for being sublime, and grandeur. Instead, Debata points out the hero Santiago makes a breakthrough in the connotation and transcends the traditional function of heroes since Santiago is not always strong-minded, tough, sturdy, but rather dualized. In his research paper, Debata describes Santiago as a hero who is both animated as well as restrained, and seems to possess great spiritual energy. In the novel The Old Man and the Sea, the old man Santiago hooks the great marlin and fights with epic skill and endurance. But eventually, his hard earned prize, the huge marlin falls prey to the sharks. The contrast, one the one hand, reveals that Santiago is animated and powerful as he manages to kill the huge marlin. However, on the other hand, it also exposes that Santiago’s power is restrained and limited since he fails to protect his trophy.

Besides, many studies (e.g. Deva, 1981; Lall, 1981; Malik & Karuna, 2015) also point out that there is parallel between Hemingway and his literary works. The study conducted by Deva (1981) proposes that Hemingway’s literary genius comes to be moulded by his personal experiences in life. Lall (1981) also puts forward that Hemingway takes for his themes some of the central experiences of his own generation and the generation that followed, which are bred in an age of devastating war and violence. However, Malik and Karuna (2015) further state that Hemingway does not rid himself of the memory of his wounds by writing about it; on the contrary, he writes about it again and again and over a long period of years. On the one hand, he really wants to lose such a memory. On the other hand, he values it and it is an important part of his writing.文献综述