His 1965 monograph about Georg Trakl, which set a standard for his understanding and the hermeneutic approach, is worth reading even today. Some of its key sentences are quoted here.
His work, consisting of the purest lyric poetry, remarkably narrow in volume and peculiar monotonous in its mostly pessimistic statement, is from a mythical, magical beauty.
Trakl's fantasies in the unity of their symbolic content are comparable to fairy tales or myths, however, they embody the internal destinies of one single individual and hence the development of a whole personality can be revealed, almost offering the ideal picture of a neurotic system. This is structured here primarily by two conditions: by ingeniousness and a youthful sexual transgression.