dates to the 1953 book Applied Imagination, in which advertising veteran Alex Osborn first articulated how a well-managed group could generate more ideas than the same number of individuals thinking on their own.
It goes on to show how the term has become a muddled catchall for anything related to creativity since the term became popular. Libby argues that over time Osborn's brainstorming's framework has disintegrated and that
many “brainstorming” sessions undermine his four key principles: focus on quantity instead of quality; allow no criticism; welcome far-fetched ideas; and encourage the group to improve ideas by combining them.
It's worth a glance and also points out how to avoid common mistakes and get the most out of brainstorming meetings.