Sackson's book is exceedingly important as a comprehensive review of Joseph ibn Kaspi's activity in, and contribution to, medieval Jewish philosophy. Ibn Kaspi is certainly worthy of critical and general attention, which he receives in Sackson's thorough work.

The first chapter of the book gives a reliable and detailed summary of all the research conducted so far on Ibn Kaspi, starting from his birth and other biographical information. Sackson gives great attention to Ibn Kaspi's philosophical approach as informed by the famous disputes about the appropriateness of studying Maimonides's works, especially the dispute of 1305, in the days of the Rashba (Solomon ben Adret).

The goal of the second chapter is to demonstrate consistency between Ibn Kaspi's writings and his approach to the definition of philosophy. Sackson compellingly argues that, much like ancient philosophers, many medieval philosophers such as Ibn Kaspi saw philosophy as a way of life, the purpose of which is human perfection. Sackson impressively combines Ibn Kaspi's approach with a number of theories that differentiate between modern and ancient philosophy: “Ibn Kaspi wrote books in order to assist the capable few in working to approach a state of human perfection and achieve a state of human flourishing” (71).

Here it is appropriate to mention Aviezer Ravitzky's thorough study that distinguishes between Maimonides's approach to the education of others, and that of the radical Maimonidean school in Provence (which included Samuel ibn Tibbon and Ibn Kaspi). Ravitzky shows that Maimonides combined leadership with community service, while his radical followers such as Ibn Tibbon and Ibn Kaspi held that a scholar should not waste time educating the masses. As Ibn Kaspi himself writes on page 60 of Tirat kesef: “One who aspires to reach true perfection should spend little time on material things and should seldom condescend to lead and educate the people.”

The third chapter deals with Ibn Kaspi's translations of Maimonides's works and his commentary on the Guide of the Perplexed. In this chapter as well, Sackson importantly clarifies what we know about Ibn Kaspi's commentaries on the Guide. That said, there are a few weaknesses and issues not given proper treatment in his discussion. On page 110, Sackson quotes a passage from Ibn Kaspi about the “pedagogical dilemma” faced by the prophets. One of the “two pains” they faced was that “if [the multitude] were to believe that He exists, they would believe that He is a body or a corporeal faculty, in accordance with the generation of the people of Enosh.” It would have been important to point out that Ibn Kaspi does not agree with Maimonides on this matter. According to Ibn Kaspi, Enosh's generation believed in a corporeal god. According to Maimonides in the Mishneh Torah (Laws of Idolatry 1:1–2), the belief in God of the people of Enosh's time was proper in and of itself—they were simply under the erroneous impression that He wanted them to worship the entities close to Him: “In the days of Enosh, mankind made a great error, and the wise men of the generation gave poor advice; Enosh himself was among those who erred. This was their error: they said, ‘Since God created these stars and orbs to lead the world, and He placed them in the heavens and gave them honor, and these are the servants who serve before him, they are worthy of praise and glory and honor.’”

Another issue worth mentioning is that of scriptural contradictions. Sackson writes: “Maimonides states there that his book itself will contain contradictions only of the fifth and seventh kinds, but Ibn Kaspi is here referring not to contradictions in the Guide itself, but rather to those in the ‘books of the prophets’ (including the Torah of Moses), which he understands as being targeted to both the philosophical elite and the unlettered multitude. Indeed, this claim is compatible with Maimonides’ own words in the introduction to the Guide” (112). Based on Sackson, it would seem that Maimonides thinks that contradictions of the seventh kind exist in Scripture, but in the introduction to the Guide Maimonides explicitly expresses doubt on this matter: “Contradictions traceable to the seventh cause occurring in the prophetical works require special investigation; and no one should express his opinion on that matter by reasoning and arguing without weighing the matter well in his mind.”Footnote ¹ On the other hand, Ibn Kaspi, unlike Maimonides, attributes contradictions of the seventh cause to Scripture.

There is one notable translational weakness: Sackson translates the Hebrew word po‘el as “cause.” For example, Ibn Kaspi's sentence כי הוא הפועל, ואם תרצה אמור: הוא הסיבה הפועלת (100) is translated by Sackson, “He is a cause—if you prefer, say that He is the efficient cause” (136). However, Kaspi consistently follows Maimonides's distinction between po‘el (Friedlander: agens) and sibbah, “cause,” in the Guide (1:69): “The philosophers, as you know, call God the First Cause [in Hebrew ‘illah and sibbah]: but those who are known by the name of Mutakallemim are very much opposed to the use of that name, and call Him Agens, believing that there is a great difference whether we say that God is the Cause or that He is the Agens.”

In the fourth chapter, Sackson provides a good summary of what is known from existing research about the Jewish tendency to follow Plato rather than Aristotle in matters of politics. Sackson makes an important distinction between al-Farabi and Maimonides, on the one hand, and Ibn Rushd's understanding of Plato, on the other, although it is left unclear how this manifests in the world of Ibn Kaspi. The other interesting section discusses Ibn Kaspi's summary-commentary of Plato's Republic. This is an extremely important and fascinating text in and of itself. Making this text accessible to a general audience, including a proper introduction, is no small feat.

In the fifth chapter, Sackson makes a compelling and in-depth argument that it is difficult to consider Ibn Kaspi a political Zionist, as many past researchers have attempted to do, for a number of reasons. First, Ibn Kaspi describes the return to the Holy Land in theoretical or even polemical terms, absent of any call to action. Second, Ibn Kaspi does not see the Jews’ situation in exile as particularly dire. The situation is not one that requires some sort of solution in the Jews’ return to their homeland. Analyzing future scenarios, Kaspi claims that it is possible to conceive of an alignment of political factors that would allow for Israel's return to its homeland.

To conclude, this important book is remarkable in that it summarizes Joseph Ibn Kaspi in an accessible English monograph. One hopes that through this monograph, this interesting philosopher will become better known among readers of English. This book's publication is a great blessing for both academics and English-speaking Torah scholars.