The Jewish history along, many "Otsarim" have been created concerning many of the various life and knowledge subjects.
With an illustrative purpose some of them are given here so that user can get an idea of which kind of work an Otsar is: compilation, collection, catalog.
1. Otsar Hasefarim (Catalog of Books)
This was the work of Isaac Benjacob. It was published in 1880 by his son, Jacob. It lists, in alphabetical order by title, Hebrew (and a selection of Yiddish) works, published until the year 1863, printed as well as handwritten. It registers about 15,000 titles. The number of manuscripts included in this Otsar has been estimated at about 3,000.
2. Otsar Hasofrim (Catalog of Writers)
A Jacob Benjacob's work. It consisted of 18,000 bio-bibliographies of writers, translators, editors and publishers of Hebrew works. It is no more extant.
3. Otsar Hateshuvot (Catalog of Responsa)
This was Rabbi Mordecai Shochetman's work (died in New York in 1948). It was intended to index and abstract legal matter in responsa literature. It is not know what became of it.
4. Otsar Hashe'elot Uteshuvot (Catalog of Questions and Answers)
It appeared in Jerusalem in 1971. Compiled by the students and scholars of the Machon Maharshal Talmudic Seminary, this is an Index of legal matter. Edited by Menachem Nachum Schapiro (born 1915), it included material from about 900 responsa volumes.
5. Otsar Targumim Ivrim Misifrut Ha'anglit
Compiled by Israel Schapiro (1882-1957), head of the Hebraic Section of the Library of Congress, it was published in New York in 1929.
It registers 259 titles of translated belles-lettres and scientific works available in the Library of Congress. The entries are arranged alphabetically by the names of the authors.
It was updated in 1950 by Jacob Israel Dienstag (born 1912), a librarian at Yeshiva University in New York.
6. Otsar Targumim Ivrim Misifrut Hagermanit
A Bibliography of Hebrew Translations of German Works.
Published in 1934 in New York, this is Israel Schapiro's work. It includes 538 titles. The list is followed by an Index of authors (in Roman characters) and titles (in Hebrew characters).