Death and Life of Great American Cities in 1961, claimed to be "one of the most influential books in the short history of city planning". She attacked the garden city movement because its "prescription for saving the city was to do the city in" and because it "conceived of planning also as essentially paternalistic, if not authoritarian". The Corbusians on the other hand were claimed to be egoistic. In contrast, she defended the dense traditional inner-city neighborhoods like Brooklyn Heights or North Beach, San Francisco, and argued that an urban neighbourhood required about 200-300 people per acre, as well as a high net ground coverage at the expense of open space. She also advocated for a diversity of land uses and building types, with the aim of having a constant churn of people throughout the neighbourhood across the times of the day. This essentially meant defending urban environments as they were before modern planning had aimed to start changing them. As she believed that such environments were essentially self-organizing, her approach was effectively one of laissez-faire, and has been criticized for not being able to guarantee "the development of good neighbourhoods". The most radical opposition was declared in 1969 in a manifesto on the New Society, with the words that: The whole concept of planning (the town-and-country kind at least) has gone cockeyed … Somehow, everything must be watched; nothing must be allowed simply to “happen.” No house can be allowed to be commonplace in the way that things just are commonplace: each project must be weighed, and planned, and approved, and only then built, and only after that discovered to be commonplace after all.Another form of opposition came from the advocacy planning movement, opposes to traditional top-down and technical planning. Modernist planning Cybernetics and modernism inspired the related theories of rational process and systems approaches to urban planning in the 1960s. They were imported into planning from other disciplines. The systems approach was a reaction to the issues associated with the traditional view of planning. It did not understand the social and economic sides of cities, the complexity and interconnectedness of urban life, as well as lacking in flexibility. The 'quantitative revolution' of the 1960s also created a drive for more scientific and precise thinking, while the rise of ecology made the approach more natural. Systems theory Systems theory is based on the conception of phenomena as 'systems', which