Levi's book on Leibnizian calculus Raphael Levi learned from Leibniz at a late stage in Leibniz's career. This might be a definite advantage for understanding Leibniz. Leibniz did not elaborate some of the philosophical principles behind the calculus until quite late in his career. If he conveyed them to Levi the latter might have included some interesting explanations in this text. Some examples: 


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*Does Levi comment on the nature of infinitesimals: fictions? ideal entities? 

*Does Levi mention the idea that equality is a generalized relation of equality "up to", in line with the Leibnizian "transcendental law of homogeneity" which he did not elaborate explicitly until 1710? 

*Does Levi say anything about the law of continuity along the lines of Leibniz's fairly late text "Cum prodiisset" (1701)? 
Two books on Leibnizian calculus were published by his secretary Rafael Levi, see http://opac.tib.uni-hannover.de/DB=1/LNG=EN/CHARSET=iso-8859-1/CMD?ACT=SRCHA&IKT=1016&SRT=YOP&TRM=Raphael+Levi&Submit=go Does anyone know anything about those books? What's in them? 
The main title of the two books seems to be:
Calculus differentialis oder Rechnung des Unendlichen des Herrn von Leibnitz 
The books date from 1747 and 1776. Thus they appear to be different from the ones mentioned in Beenakker's answer in the name of Schwarzschild. I haven't been able to get a pdf to see what the introduction says. If anyone has the pdf I would appreciate it.
The 1776 entry: http://opac.tib.uni-hannover.de/DB=1/XMLPRS=N/PPN?PPN=031333311 is in manuscript. Whoever has access please let me know.
 A: This is what Steven and Henry Schwarzschild write here about these works of Rafael Levi, which indeed seem to be his own research, based no doubt on what he had learned from Leibniz:

In his scholarly capacity Levi published several books over the
  decades. They are essentially pedestrian in content and reflect his
  two areas of expertise - in German on commercial arithmetic, and in
  Hebrew on Jewish astronomical calendration. By thus putting into
  literary practice his commercial philosophico-mathematical training as
  well as his Jewish learning, Levi served in a double-barreled way the
  Jewish mercantile class and the religious leadership (typically
  combined in personal union).

The mathematical works of Rafael Levi include:


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*Vorbericht vom Gebrauch der neuerfundenen Logarithmischen
Wechseltafeln + Supplement (Frankfurt-Hannover 1747/1748/1749)

*Vorbericht zum Gebrauch der neuerfundenen logarithmische Wechsel-Tabellen, wodurch ein Cours aus 2. 3. oder mehr gegebene Coursen bloß durch addiren und subtrahiren kan gefunden werden (Frankfurt-Leipzig 1749).
This has been scanned and can be accessed from here.


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*Rechnungsmethode (Hannover 1783, edited posthumously by Meyer Aaron)

