Character Analysis
Susie is Dan's, well, not quite girlfriend… but lady friend who pays him amorous visits (as Dan describes their nights together) at the opening of the novel. Despite an exception or two, Dan increasingly neglects her over time as he gets deeper into his training with Socrates.
So, she basically serves to illustrate how he is leaving his old, conventional life in favor of the peaceful warrior's way. However, Linda—who shows up toward the end of the novel—doesn't get pushed aside; he marries her! Perhaps this is because Susie takes up more of Dan's time, and Linda is willing to deal with the limitations on their relationship imposed by his training.