This is the genealogy of architecture in the 20th century by Kenneth Frampton the doyen of architecture history. His approach is impressively clear: he traces four lines that are recognizable as the powers that propel renewal in architecture. He structures his observations by focusing on the relevant periods in the following order: 1st, the Avant-Garde (1887 1986); 2nd, organic architecture (1910 1998); 3rd modern and national styles (1935 1998), and 4th, industrialization and prefabrication (1927 1990). His overview is not a lexical collection of chronological sequences. Instead, his insights stem from his confident eye for the history, theory and motives behind architecture. He also follows the steps of the great architects of the 20th century.