"Sketch No. 75" is one of over eighty drawings executed during a period of eighteen months in 1939-40, while Jackson Pollock was under the Psychotherapeutic care of Dr. Joseph L. Henderson in New York City. Pollock had been recently discharged from a New York hospital to which he had committed himself for treatment of acute alcoholism. Dr. Henderson had been recommended through a close friend because of his training with Carl. G. Jung of Zurich.
Pollock was withdrawn and inarticulate in his early sessions with Dr. Henderson. In an effort to open communication, the artist brought his drawings as an aid to discussion. These were the drawings Pollock began following his hospitalization, they were part of his work-in-progress, and were discussed in the language of art criticism. The psychological development shown in a few of the drawings was only made clear years later when Dr. Henderson studied them in connection with his research into the symbolism of the unconscious. With the drawings Pollock became better able to discuss his emotional problems. Henderson recalls " ...I was compelled to follow the movement of his symbolism as inevitably as he was motivated to produce it." The period of the psychotherapy corresponds not only with gathering of forces on Pollocks part, which somehow enabled him to sustain a high degree of productivity for the succeeding years, but also a period of dramatic change in his art, during which he cast off previous models, taking on a new awareness of visual symbology.