Dr. Jacobi prepared some 400 genealogical studies, mainly on European rabbinical lineages. He developed 100 of these studies into 114 “monographs”, contained in type-written, loosely bound work-books, which have been largely, but not fully, indexed.

Each of the 114 monographs comprises one family through the male line from its earliest known progenitor, duly listing spouses as well as the known descendants of such daughters as were married to husbands, whose own families lack a specific monograph. Each monograph begins with "General Notes" explaining the etymology of the family name, its historical and geographical origins and the family's inter-relationships with other families (shown sometimes in charts called “excursuses”). In addition, the monographs include bibliographies, indices of the given names of the particular family examined and of the affiliated families within that monograph.

Most important for genealogists are the "Tables (charts) of Descent" and the biographies of leading personalities on various family trees. There are also the "Biographical Notes" on every known member of the family and his or her spouse(s). These Notes include all family names and surnames (frequently more than one) and given names (on occasion, up to five), which were written in the German transliteration from Hebrew, Yiddish or other languages. Then the dates of birth, residence and death are given, as well as the person's publications, if any, and finally the bibliographical and other sources for information on each person. Sometimes more than a page is devoted to a single individual, while others may be attributed just one line or simply an abbreviated note – "p.d." [provenance doubtful].

Absolute Generations

In researching so many families, sometimes going back more than 15 generations, Dr. Jacobi employed his unique system of “Absolute Generations” to record the individuals in the monographs and to synchronize them within their own and other kinship groups - and, at the same time, to harmonize their generations with wider frames of reference, both historical and societal.

Use of the Monographs

Dr. Jacobi’s 100 monographs, in the 114 work-books, are available for study and research in the Judaica Reading Room at the National Library of Israel, on the Hebrew University’s Givat Ram Campus in Jerusalem.

The work-books cannot be sent elsewhere or be copied/reproduced in any form (microfilm, microfiche, Xerox, etc.) for use outside the Library.

An Index of the Monographs/work-books was prepared as a CD by volunteers from the Israel Genealogical Society, for the International Association of Jewish Genealogical Societies Conference in Jerusalem in 2004. The Index contains first and family names, dates of birth and death, the name of an individual’s father (patronymic) as well as the identifying table-chart, absolute generation and sibling order references. The family names are recorded in alphabetical order on the CD-ROM, for easy identification of individuals mentioned in the monographs. The Israel Genealogical Society may be approached for purchase of copies of the CD (if any remain).

The Institute holds the rights to the entire Jacobi collection. It seeks to index, edit and publish the complete corpus of Jacobi’s genealogical work. Persons interested in purchasing the copyright to a specific monograph in order to publish it and thus contribute to the publication of the whole collection should contact the Director of the Institute.

Click here for list of the 114 Monographs.

Click here for a description of the “Jacobi Absolute Generations Scale”.