Koolhaas's book Delirious New York set the pace for his career.
Koolhaas analyzes the "chance-like" nature of city life: "The City is an addictive machine from which there is no escape" "Rem Koolhaas...defined the city as a collection of “red hot spots.” (
Anna Klingmann).
 As Koolhaas himself has acknowledged, this approach had already been evident in the Japanese Metabolist Movement in the 1960s and early 1970s.

A key aspect of architecture that Koolhaas interrogates is the "Program": with the rise of modernism in the 20th century the "Program" became the key theme of architectural design.
The notion of the Program involves "an act to edit function and human activities" as the pretext of architectural design: epitomised in the maxim form follows function, first popularised by architect Louis Sullivan at the beginning of the 20th century.
The notion was first questioned in Delirious New York, in his analysis of high-rise architecture in Manhattan.
An early design method derived from such thinking was "cross-programming", introducing unexpected functions in room programmes, such as running tracks in skyscrapers.
More recently, Koolhaas unsuccessfully proposed the inclusion of hospital units for the homeless into the Seattle Public Library project (2003).
Koolhaas's book Delirious New York set the pace for his career. Koolhaas analyzes the "chance-like" nature of city life: "The City is an addictive machine from which there is no escape" "Rem Koolhaas...defined the city as a collection of “red hot spots.” (Anna Klingmann).  As Koolhaas himself has acknowledged, this approach had already been evident in the Japanese Metabolist Movement in the 1960s and early 1970s.
A key aspect of architecture that Koolhaas interrogates is the "Program": with the rise of modernism in the 20th century the "Program" became the key theme of architectural design. The notion of the Program involves "an act to edit function and human activities" as the pretext of architectural design: epitomised in the maxim form follows function, first popularised by architect Louis Sullivan at the beginning of the 20th century. The notion was first questioned in Delirious New York, in his analysis of high-rise architecture in Manhattan. An early design method derived from such thinking was "cross-programming", introducing unexpected functions in room programmes, such as running tracks in skyscrapers. More recently, Koolhaas unsuccessfully proposed the inclusion of hospital units for the homeless into the Seattle Public Library project (2003).
Rem Koolhaas