Humanistic psychology focuses on psychological health rather than on mental illness. "Its view is optimistic, with an emphasis on the human potential. It's a healthy viewpoint. In 1942, Rollo May was stricken with tuberculosis. After eighteen months in a sanitarium in upstate New York, he decided that his attitudes and his personal will were more important to his recovery than the treatments. He entered the graduate psychology program at Columbia University in New York City, receiving his Ph.D. in clinical psychology in 1949 with the highest honors. In the decades that followed, May's dissertation, The Meaning of Anxiety, published in 1950, and revised in 1977, had a major influence on the development of humanistic psychology" (Crompton).
Rollo May argued that culture was in an "age of anxiety" and, furthermore, that channeling his own high anxiety was a major factor in overcoming his tuberculosis. (This would be the first we've heard of the mind/body connection to illness in the field of psychology I believe.) May was one of the most influential American psychologists of the twentieth century. He helped to introduce European existential psychoanalysis to an American audience. He was a founder of humanistic psychology, with its focus on the individual, as opposed to the behaviorist psychology and Freudian psychoanalysis that was prevalent in the 1940s and 1950s. .
May's writings were both practical and spiritual and they promoted the power and worth of the individual. As such, they contributed to the development of the human potential movement. May maintained that widespread alienation and anxiety were a result of breakdown and upheaval in culture and society, rather than the result of individual psychological problems. I would add that the lack of spiritual awareness is another component of breakdown and upheaval. .
Maslow's thinking was surprisingly original - most psychology before him had been concerned with the abnormal and the ill.