Rollo May was an influential American psychologist who helped develop existential psychotherapy. Some key aspects of his approach included:
1) He drew from existential philosophy and emphasized an individual's subjective experiences and freedom to make choices.
2) Therapy aimed to engage patients in using their freedom by reevaluating past experiences that caused freedom to become anxiety-inducing.
3) By finding meaning and purpose, even in suffering, patients could rediscover their ability to shape their own existence.