Today’s highlight is another seventeenth-century book printed in Amsterdam by Johannes Jodocus Janssonius (shelfmark: W F823; see also, Constantijn L’Empereur’s commentary on the Book of Daniel). The “Extraordinary Professor of Semitic Languages” at the University of Koenigsberg, Johannes Stephanus Rittangel (1606-1652) published his Latin translation of Sefer Yetsirah. This was the third latin translation and the first bilingual publication of the famous book of Jewish mysticism. It is not clear whether Rittangel was a converted Jew or a temporary convert to Judaism. He certainly had an excellent command of Hebrew and spent decades among Jews including Karaites of Lithuania. On his way from Lithuania to Konigsberg in 1640 or 1641, he wanted to stop in Amsterdam to publish his translation of Sefer Yetsirah. However, his ship was attacked by pirates and he ended up in England, where he got acquainted with famous Christian Hebraists such as Samuel Hartlib, John Dury and John Selden. He finally published the book in 1642. Although he was undoubtedly knowledgeable, “his abrasive and difficult personality” “made him impossible to deal with” (for more on him, see Daniel J. Lasker, “Karaism and Christian Hebraism: A New Document,” Renaissance Quarterly, 59:4, [Winter, 2006]: 1089-1116).