Encyclopedias are purportedly all-encompassing, authoritative presentations of information compiled mainly by experts for an audience of non-specialists. Believed to offer only universal ‘facts’, they have long been associated with objectivity. Yet, by arranging information into a usable form, encyclopedias inevitably convey particular ideologies and ideals. As a result, they offer a lens into the changing ‘truths’ upheld by or expected of readers. This article compares three successive, high-profile Japanese encyclopedias, each bearing the title Sekai bunkashi taikei [Encyclopedia of world cultural history]. Somewhat differently from today, the field of world cultural history purported to ‘objectively’ cover the widest relevant space (earth) and time (the human past). However, the specific concerns and commitments of world cultural historians changed greatly between the 1920s, when the first encyclopedia was published, and the 1960s, when the final volumes of the third series appeared. By looking closely at both the production and consumption of these texts, this article shows the deeply politicized ways in which ‘objective’ knowledge of the world was interpreted, implemented, marketed, and received by the Japanese public during the years of nation-building, imperial expansionism, and the Cold War.