BERLIN

THIS quiet, orderly man, who lives in a quiet, orderly house, in a very quiet tree-lined neighborhood has caused a huge public stir here with his volatile book arguing that Muslim immigrants in Germany are socially, culturally and intellectually inferior to most everyone else.

With the certainty of an accountant adding up rows of numbers, Thilo Sarrazin has delivered his conclusion in a book that has sold over one million copies, forced him to quit his job at the German central bank, may get him kicked out of his political party and for the first time since World War II made it socially acceptable in Germany to single out a particular minority for criticism.

“The facts I quoted and analyzed are undeniable and cannot be done away with,” he said without a hint of defensiveness in his quiet, understated manner.

Mr. Sarrazin, 65, is tall and trim, with a head of thick grayish hair, round tortoiseshell glasses and a right eye that is always squinting, as if looking into the sun. Friends of Mr. Sarrazin say they are not at all surprised that he has found himself in this position because while he is quiet and orderly, he also has a penchant for offending.