Brainstorming is a group technique to generate ideas for solving a problem by having members spontaneously contribute without criticism. It was popularized by Alex Osborn in 1953. There are two types: individual brainstorming allows freedom but limits input, while group brainstorming leverages the full experience and creativity of all members to build upon each other's ideas. Effective group brainstorming requires preparing the group, clearly presenting the problem, guiding a discussion to develop ideas, and later analyzing the ideas to select the best ones. The process encourages wild ideas and forbids criticism to allow creativity to flow.