Rittel and Webber introduced the concept of "wicked problems" in 1973 to describe a certain type of complex problem that existing problem-solving approaches could not adequately address. They defined wicked problems as having unclear requirements and solutions that are difficult to identify and involve complex interdependencies. While others had previously discussed increasingly complex problems, Rittel and Webber distinguished wicked problems as a unique problem domain requiring a new approach focused on problem understanding rather than definitive solutions. Rittel suggested dialogue among stakeholders as a "second generation" approach to address wicked problems.