For most of human history groups of people have operated to restrict the flow of knowledge for the benefit of the controlling group. Technological advancement has exploded since governments began to incentivize release of information through the concept of patents.

Some examples...

See "guilds" https://en.m.wikipedia.org/wiki/Guild

See "companies" with "trade secrets".

See Vatican Library (no longer fully secret) https://en.m.wikipedia.org/wiki/Vatican_Library

See "classified information" https://en.m.wikipedia.org/wiki/Classified_information