Purpose of Preamble-

-It indicates source of Constitution- 'We the people of India.'

-It throws aim and objectives of the Constitution.

-Concept taken from- US.

-Pattern of writing/language- Australian constitution.

-Influenced by government of India Act- 1919.

-Objective resolution introduced by- Pt. Jawahar Lal Nehru- 13th December 1946 and passed by common consensus on- 22 January 1946.