What is the difference between Charlie in the beginning of the story and Charlie at the end of the story?

The difference between Charlie at the beginning and the ending of the story Flowers for Algernon by Daniel Keyes lies in his degree of contentment. The story tells of a man of low IQ who is subjected to a surgical procedure that makes him brilliant. The effect is temporary, however, and Charlie gradually loses all the complex intelligence he has gained and reverts back to the simple man that he once was.

At first, one might say that Charlie at the end has not changed at all from how he was in the beginning, and this is true as far as his mental capacity is concerned. However, in the beginning, Keyes establishes a relationship between Charlie and those around him based upon his simplemindedness. His co-workers often tease him, and he goes along with it because he doesn't understand that their motives are insincere. When he becomes intelligent, he realizes that his co-workers are not true friends and quits his job. As his intelligence leaves him, he goes back to his old job and his class, but his co-workers, landlady, and teacher no longer treat him with joviality and kindness. Instead, they pity him, and it's the pity that creates a lack of contentment that Charlie did not feel previously.

In the end, Charlie decides to leave, something that he never would have considered before. He takes a few books along, hoping that if he studies hard, he might regain a little of his intelligence. This ambition is also a change from the beginning, when he was content with his simple situation.