He is known today primarily for his landmark, two-volume edition of Callimachus and the two volumes of his History of Classical Scholarship, in addition to numerous articles and lectures related to these projects and to the fragmentary satyr plays of Aeschylus and Sophocles.

[2] The boy's grandfather Jakob, also a printer, had purchased the house of the humanist Konrad Peutinger, and Pfeiffer would later consider it a special stroke of fate that he had been born and bred in the former home of a central figure from the golden age of humanism in Augsburg.

[7] He dedicated his dissertation as an uxori carissimae sacrum, Latin for (roughly) "a gift of devotion to a wife most dear"—namely, Lili (née Beer), a Jewish painter from Hungary whom he had married earlier in 1913.

[5] His first passion during this period of renewed activity was the steadily accruing papyri of Callimachus, several of which he had studied in Berlin before the war with Wilhelm Schubart, the foremost literary papyrologist of the age.

[11] The stability afforded by this new position allowed Pfeiffer to not only redouble his focus upon Callimachus and Greek literature in general, but also to return to a topic which had from his youth held a special interest for him: the history of humanism and classical scholarship.

But Callimachus remained his primary focus, and a series of articles on the still further fragments which were being published at this time solidified his reputation as the foremost scholar of the poet's work, and in 1934 he was recognized as a full member of the Bavarian Academy of Sciences and Humanities.

In his obiturary of Lobel, Sir Eric Gardner Turner wrote, "The partnership over Callimachus with Rudolf Pfeiffer went well on both sides, and ended in mutual affection and esteem and a notable edition of the poet.

[15] In the History of Classical Scholarship, which he published in English despite having returned to Munich, Pfeiffer drew parallels between the intellectual world of Hellenistic Greece and that of his fellow German exiles, particularly in the case of the scholars who fled Alexandria following the accession of Ptolemy VIII Physcon in 210 BCE.