The Fountainhead is a novel about the triumph of the "selfish" individual. The true individual acts not only without regard for the influences of others, but with complete concern for self. This is not concern for one's own advantage or pleasure, but knowledge of one's own goals and the willingness to achieve them. Roark, the individual in every way, is "selfish" because he has and uses this total self-understanding. The conventional definition of the word "selfish" is "focused on wealth, power, or pleasure for the self," but Rand uses it to mean only "focused on self." In Rand's sense, a "selfish" individual would be in no way conventionally selfish, because wealth and power matter only in comparison with others" wealth and power. Neither has any intrinsic value for the individual. Roark is called "selfless" by the bank chairman because he is poor and "[needs] the commission" (197) he refuses - he is not concerned with the money - but he is, in fact, "selfish" because he makes his own decisions and does not let the wishes of others change them. If he had compromised his design by letting others change it, only then would he have become selfless, because he would not have followed his own vision.
In order to act as a person alone, untainted by outside forces, that person must have full self-understanding, and must make each decision according to his or her own desires and goals. Roark is a true individual; most people are not. Self-understanding is difficult to attain for the average person not because the human soul is in itself inscrutable, but because men and women are so confused by outside influences that they incorporate those influences into their own being. For most people, understanding yourself is the process of digging through the accumulated layers of conventional knowledge to find the deeper knowledge and will within. Roark, on the other hand, doesn't have to deal with those plaque-like layers.
