Isaac ben Eliyakim of Posen

The only two things we know about Isaac ben Eliyakim are that he wrote the Yiddish book Lev tov (A Good Heart), and that he had some undefined connection to the city of Poznań in Poland. Lev tov, first printed in Prague in 1620, is an example of the genre of Yiddish-language ethical works known as sifre musar (morality books), which were meant to provide general religious and moral guidance in the vernacular shared by Ashkenazic Jews of the time. Printed frequently, even in present times, Lev tov was warmly recommended by such authorities and authors as Shabbetai Sheftel Horowitz, Glikl Hamel, and Jonah Landsofer.