In 1969, the producers of the Harvard Lampoon parodies of Life and Time, Douglas Kenney, Henry Beard, and Robert Hoffman had meetings with 21 Century, and together licensed the "Lampoon" name for a monthly national publication, National Lampoon, which became very successful and spun-off various books, records, radio shows, off-Broadway plays, and movies.
21st's next magazine was the revival of Liberty, which they published from 1971-1973.
In 1977, they started publishing Heavy Metal.
In 1979, 21 Century was re-named National Lampoon, Inc.
In 1989, the company was sold to new owners, but no other changes were made.
In 1990, the company was sold again, and the new owners merged it into their J2 Communications, a movie company.
In 1992, Heavy Metal magazine and its affiliates were sold out of the company.
In 1998 the last issue of National Lampoon was published. The company still exists as a movie related business. Does this data need corrections? Become an editor.