Sefer HaChaim is an ethical work by Rabbi Chaim ben Betzalel of Friedberg, the older brother of the famed Maharal of Prague (Yehuda Loew ben Betzalel), written while Rabbi Chaim and his family were quarantined due to a 1578 plague. The author’s introduction describes his worries over the plague as well as the potential loss of time from Torah study and how he found comfort by using the time to fulfill a longstanding student request, that he compile a book of inspirational teachings offering guidance in various areas of life. This work is the Sefer HaChaim, the Book of Life, as he felt it was life-giving work in dark times.