The details of Chris’ graduation and then the beginning of his fatal adventure are detailed in Chapter 4.
The reader is told that he graduated in May 1990 and that his family attended his graduation service. He gave his mother a Mother’s Day gift, which was out of character as he had made the decision to refuse to give or receive gifts two years previously.
Chris was frustrated that his parents wanted to buy him a new car as a graduation present, and in the letter he wrote to his sister at the time shows that he was quite contemptuous of their lack of understanding of him-
“…I’m going to have to be real careful not to accept any gifts from them in the future because they will think they have bought my respect.”
Chris’ rejection of his parents and their ideals is further illustrated by the fact that he had his mail held before being returned to his parents so they were not aware that he had left over a month earlier. He carefully plans his departure to give himself maximum freedom:
To symbolize the complete severance from his previous life, he even adopted a new name. No longer would he answer to Chris McCandless; he was now Alexander Supertramp, master of his own destiny.