This research project tries, for the first time, to analyze and compare all the key Spanish Jewish apostates, especially Petrus Alfonsi, Abner of Burgos, Geronimo de Santa Fe, Pablo de Santa Maria and Pedro de la Caballeria. The aim of this research is to understand the ideological background of the mass conversion of the Spanish Jewish community from the perspective of the intellectual elite involved in the conversion itself and not – as has usually been the case in modern scholarship – according to the rabbis who decided to stay Jewish. In the first part of the book, the author explains the impact of the conversion of a part of the Jewish intellectual elite on the Spanish Jewish population. In the second part, he examines the opinion of the various ideological converts regarding Christianity (especially the dogmas of the Trinity and Incarnation). In the third part, he analyzes their criticisms of Judaism. The main conclusion of this research is that there is a very important difference between the various converso intellectuals regarding the essence of Christianity. The conversos who were philosophers or kabbalists before their conversion continued with a similar approach even after their conversion, using their former philosophical/kabbalistic knowledge to try to convince their fellow Jews to convert as they had. The common denominator of the different writings of these apostates is not their opinions on Christianity but rather their similar criticisms of Judaism, and especially with regard to keeping Jewish religious obligations.

Free choice has been one of the main philosophical issues throughout the ages. The Essence of Choice in Medieval Jewish Philosophy offers a comprehensive analysis of the views of medieval Jewish philosophers on this topic. It presents various perspectives on the problem of free choice in philosophy in general and in Jewish philosophy in particular: Does free choice really exist, or is it an illusion? What is the attitude of the medieval philosophers toward what the Bible and the Sages have to say about free choice? Does Judaism have a substantive position on philosophical questions? What power can free a person from causal determinism? The book discusses at length the opinions of twenty-one philosophers, from Al- Muqammis in the ninth century to Rabbi Joseph Albo in the fifteenth. This engagement with many philosophers demonstrates the richness of Jewish philosophy and the multiplicity of opinions in it, as well as how historical changes, such as the transition from Arabic to Hebrew, affect philosophical thought. On the basis of his historical analysis, the author argues that there is no fundamental Jewish position on the question of free choice and that one can find support in the religious texts for every philosophical view.

Tarbiz is the only Hebrew academic journal that is devoted to the entire range of Jewish studies. Appearing quarterly, this journal is the principal forum for the expression of the most important developments in Jewish studies in our generation, and its contributors include the leading scholars in the various fields of Jewish studies in Israel and the world, as well as young scholars who are beginning to make their mark. Tarbiz was first published in 1930 at the Institute of Jewish Studies at the Hebrew University of Jerusalem, under the editorial pen of Prof. Jacob Nachum Epstein z"l.