The first efforts towards creating an underground archive were undertaken as early as in May 1940, but work got underway in earnest in November of that year, after the ghetto was finally sealed, which took place on 15 November 1940. The mission of Oneg Shabat (OSh) was to document, day by day, the events in the ghettos in the Polish lands, in particular in Warsaw, by writing down eye-witness testimonies of Jews while they were still fresh. OSh also collected materials such as German public announcements (alternatively they copied out their wording), documents from Jewish Councils, correspondence of welfare organizations (ŻSS, Joint), underground and so-called reptilian press items, posters, documents testifying to the everyday life of the community (e.g. food ration cards, tram tickets, sweet wrappers), letters, Kennkarten, ordinances related to forced labour, legacies and papers of particular individuals, scientific studies and drafts thereof, radio bulletins, reports for Polish underground organizations, and proclamations by underground organizations (e.g. ŻOB, the Jewish Combat Organization). Among the most important of these documents is a collection of the ghetto underground press (around 40 titles), diaries written on a regular basis by various people, drawings (e.g. those by Gela Seksztajn), and photographs. The majority of the documents are in manuscript form, some of them copied out several times. The dominant languages are Polish and Yiddish, though some of the documents were also recorded in Hebrew, some of the official materials are in German, and there are sporadic items in English, French, Romanian, Ukrainian, Russian and Italian. The ARG documentation is unique in every respect, and crucial to study of the history of the Holocaust in the GG and the former eastern borderlands of Poland known as the Kresy.

The members of OSh tried to make use of the materials they gathered in their own research and to record the history of the Holocaust as it happened. A range of research methods were used, including sociological and psychological methods, and this in part determined the selection of the materials to be gathered, which were not restricted to official documentation – the value of personal documents and the words of individuals were recognized. The OSh group encouraged people to keep journals, schoolchildren to write essays and other texts on current affairs, and those resettled from other places to write down their accounts of the fates of Jews in the small towns from which they came. OSh comprised several dozen people with strong personalities. Its secretary was Hersz Wasser – the only member of the organization who survived and knew where the archive was hidden, so enabling him to help excavate the documents from beneath the ruins of the ghetto. In the ghetto he also worked as the ŻSS secretary delegated to the Centralna Komisja Przesiedleńcza (Central Resettlement Committee).

Wasser’s deputy in OSh was Eliasz Gutkowski from the party Poalei Zion Right, who was assisted by Rabbi Szymon (Shimon) Huberband, an Agudas Isroel activist, member of the Warsaw rabbinate, and chairman of the religious section of the Warsaw ŻSS. He wrote many reports on the religious life of the Jews under the occupation, and on the destruction of the synagogues and cemeteries. Menachem Linder was responsible for the economic and statistical section, and Izrael Lichtensztajn for education. Other members of OSh were writers and poets, among them Icchak Kacenelson, Rachela Auerbach, Perec Opoczyński and Lejb Goldin. Ringelblum’s other immediate associates were Abraham Lewin, Daniel Fligelman, Nechemiasz Tytelman and Jerzy Winkler. Ringelblum himself examined the history of OSh and profiled those who formed the group in an essay written in January 1943. A year previously the group had launched a research project entitled “Dwa i pół roku” (Two-and-a-half Years). This involved research into issues such as the Jewish woman, religious life, Polish-Jewish relations, house committees, community soup kitchens, bookshops and libraries, the fate of small Jewish communities, and German-Jewish relations. Each chapter was structured chronologically. This project may be viewed as a form of summary of the work of OSh. In the foreword, Ringelblum posed a number of seminal questions as to the impact of the war on Jewish society and its future prospects in both the short term and after the war. The project was never completed.

Naturally, the initiators and founders of ARG could not have foreseen the consequences of the Nazis’ policy to exterminate all the Jews of Europe. Nonetheless, the continued acts of terror, the isolation of the Jews and their exclusion from successive spheres of life, and their annihilation through labour and the poor living conditions in the ghetto and also in direct liquidation campaigns did force the members of OSh to realize that they, too, were unlikely to survive, and that it was therefore imperative that they conceal the materials they had amassed for posterity. When, after the war, first ten metal crates (Ring. I) and later two milk cans (Ring. II), packed full of documents gathered in the ghetto, were unearthed, the world learned just how broadly the members of OSh had understood their mission. The documents they had collected reference all aspects of the life of the Jews in those extreme conditions, from the ways in which the ghetto internees procured food, to works of art and literature. They also offer insight into the way in which the Jews in various different social groups lived in that period, and by what means some of them succeeded in enduring and surviving.

The documents excavated from beneath the ruins of the Warsaw ghetto in 1946 and 1950 (hence the use of the division into Part I and Part II ARG). The first two parts of this body of materials were concealed in the basement of the Jewish school at 68 Nowolipki Street in Warsaw ; the third part of the archive, buried not later than on 18 April 1943, and possibly containing documents relating to the Bund or to the ŻOB , and perhaps also other materials , was never found.