In his lifetime, Tigerstedt was one of the leading and most respected literary historians in Scandinavia[1] and is best known internationally for his contributions to Plato scholarship.

In 1948, he left Finland and moved to Stockholm where he became a literary editor at the publishing houses Natur & Kultur and later Bonniers.

At Natur & Kultur, he became something of a pioneer in introducing modern science fiction to Sweden, and was involved in the publication of the series 'Tomorrow's Adventure.'

Later, however, when a hopeful student wanted to write his dissertation on H. G. Wells, Tigerstedt replied to his proposal with the words: "The candidate has misunderstood the subject.

'[4] Brisson's 1977 review said 'This historical argument [of Tigerstedt] is truly convincing and sheds light on many points unknown or poorly known about the Platonic tradition during the Middle Ages, through the Renaissance, and to the Enlightenment and the dawn of rigorous history of philosophy.

'[13] Tigerstedt was known among his colleagues and students for his vivid lectures, their historical outlook, and his language skills, but he was fairly dismissive of the new ideas that came to influence literary theory in the 1940s (for example, the so-called 'New Criticism' and psychoanalytic methods).

He emphasized the content of each work and genre history; as a researcher and critic he assumed that literary studies should aim to reconstruct and bring to life the author consciously thinking in the context of his time, and thus to avoid considerations that were for the most part unconscious or invisible to the poet himself.

To see an author's people and language as primarily an expression of such private emotions or his "inner creative flow" would give in to unscientific subjectivity and romantic illusions.