Yitzhak ben Yoseph Israeli. Yesod Olam [geometry, astronomy and cosmography].

As stated on the title-page, the scribe, Yitzchak Eliyahu b. Yonah, composed this manuscript in the Beth HaMedrash HaYashan of Vilna, completing it in the summer of 1769. This was during the lifetime of the Vilna Gaon - likely a reflection of the strong interests in the natural sciences that the Vilna Gaon himself encouraged having such subject matter be published in Hebrew. This manuscript predates the first edition (Berlin, 1777) which was edited from an incomplete, defective manuscript by the celebrated Baruch Schick of Shklov, a disciple of the Vilna Gaon. The second edition (1848) was published by Ber Goldberg with corrections based upon another incomplete manuscript. <<The present manuscript contains variances and more complete passages when compared to these published versions.>> A critical edition consulting all available manuscripts remains a desideratum. A careful comparison with this manuscript would obviously be a necessity. The author of the Yesod Olam, wrote this work at the request of his teacher, Asher ben Yechiel (Rosh). It is considered the most important contribution toward the study of astronomy throughout Hebrew literature.