Halacha by committee - Mishna Berura

 Rav Bluth told me that Rav Moshe had said to him, that the Mishna Berura was composed by a committee of talmidei chochomim and therefore it is more binding than if composed by an individual

I am not aware of any recognized sefer that was composed by a committee. The Rambam, Shulchan Aruch, Aruch HaShulchan, Tur, Beis Yosef etc etc were all composed by individuals and their authority comes because they were widely accepted. So why was this different?

Rav Bulman told me that the Mishna Berura was written because many cities in Europe had government appointed Rabbis who were often maskilim and were therefore  largely ignored by the yeshiva world. If a bochur or avreich needed to know what the normative practice was he had no where to go. So the Chofetz Chaim created a source book listing various views and indicating normative practice

It was not immediately accepted and even in Radin they relied on the Aruch HaShulchan. Rabbi Heineman told me  that post world war II with the loss of many poskim it was decided that their needed to be a common reference and the Mishna Berura was chosen. His rebbe, Rav Kotler always went around carrying a volume of Mishna Berura in order to increase its importance.