Taharoth HaKodesh.

A most unusual Halachic work in which the author strenuously argues against incorporating images of animals within the synagogue. This resulted in the removal of such figures from the beautifully crafted Holy Ark in Safed’s famous Ar’i Synagogue. R. Heller famously defended the observance of Lag Ba’Omer at Meron, down to the burning of expensive clothing, despite criticism from rabbinic luminaries including the Chasam Sofer (see Shu’t Chasam Sofer YD 233). The image of Meron on the title page seemingly alludes to this connection.