 The specific term 'sociology of knowledge' is said to have been in widespread use since the 1920s, when a number of German-speaking sociologists, most notably Max Scheler and Karl Mannheim, wrote extensively on sociological aspects of knowledge.With the dominance of functionalism through the middle years of the 20th century, the sociology of knowledge tended to remain on the periphery of mainstream sociological thought.It was largely reinvented and applied much more closely to everyday life in the 1960s, particularly by Peter L. Berger and Thomas Luckmann in "The Social Construction of Reality" (1966) and is still central for methods dealing with qualitative understanding of human society (compare "socially constructed reality").