A growing interest in traditional symbolism led him to Peking (1931–1933) where he spent three years studying with Baron Alexander Staël von Holstein, a Baltic refugee and distinguished scholar.
His travels would eventually take him to some of the more remote parts of the world, photographing rock carvings, visiting small museums or private collections, and talking to missionaries, scholars, or anyone else who might have information he was seeking.
After World War II, he lived in Woodstock, New York, where he began to develop his ideas, publishing learned monographs on traditional design motifs.
In 1945, the American Anthropological Association sponsored an exhibition of his photographs at the AMNH illustrating his ideas about how certain symbols were shared by widely separated cultures.
In an age before the copier and the personal computer, he accumulated an archive comprising some 200,000 photographs, 800 rubbings (mostly of petroglyphs), 18,000 pages of correspondence in multiple languages, and a bibliography of 5670 titles filed by alphabet (Chinese, Cyrillic, Latin)—all meticulously cross-referenced.
The result of twenty years of labor was Materials for the Study of Social Symbolism in Ancient and Tribal Art: A Record of Tradition and Continuity, published privately in three volumes (1986–88) and distributed free of charge to scholars and libraries throughout the world.
Schuster's archives, which contain unpublished material on a wide variety of subjects, are housed in the Museum der Kulturen in Basel, Switzerland.
Schuster's initial publications centered on traditional design motifs that he found preserved on textile fragments he had collected in western China during the 1930s.
Even where the motifs seemed specifically Chinese, like the return of the triumphant scholar (chuang yüan) on horseback, the oldest known prototypes were found in distant times and places.
Schuster used the method employed by many art historians of identifying significant design motifs and then tracing their distribution and meaning in different cultural and historical contexts, looking for commonalities.
Writing later about the difficulty of providing historical support for the idea of cultural contact between Asia and the Americas in prehistoric times, he defended his methodology.
As in linguistics, where many languages can arise from a common ancestor, he sought the underlying patterns that provided the links between seemingly disparate art forms.
It was Schuster's study of joint marks that ultimately revealed an underlying system of genealogical iconography that he believed dated from Upper Paleolithic times.
He expressed his growing excitement in a letter to a friend: He published his initial findings in Brazil in 1956 under the title, “Genealogical Patterns in the Old and New Worlds.” Its goals seemed modest enough for a work of such importance.
No examples of these furs survive from ancient times but the Tehuelche Indians of Patagonia made such robes as did other technologically simple hunting peoples.
Schuster also found abundant evidence that these designs were reproduced on cave walls, pebbles, tools, and stone monuments where they represented the corporate identify of their owners, much like military insignia do today.