Bruck was one of the most enthusiastic supporters of the Reform movement, and was among the pioneers of modern Jewish theological literature. He wrote "Die Reform des Judenthums"; but especially his "Rabbinische Ceremonialgebräuche" and "Pharisäische Volkssitten und Ritualien" are of great value to the student of Jewish customs and practises, and were favorably criticized by Geiger ("Wissenschaftliche Zeitschrift," iii. 426) and Fürst ("Allg. Zeit. des Judenthums," i. 324), and were widely read.