90 per cent of books in a typical bookstore are not worth the paper they are written on. This is NOT one of those books. The concepts presented in this book are profound. It is the best book I own.

One cannot even presume to understand modern architecture until one has read Giedion's classic work. This book did more to shape the view of modern architecture than did any other book. Giedion provides an impressive survey of architecture down through the ages, illustrating those aspects which had an influence on modern architecture. One of his more illucidating chapters is "The Demand for Morality in Architecture," which underscores the content of this work.

The heart of the book is his chapter on "Space-Time in Art, Architecture, adn Construction," in which he examines the leading figures and movements in modern architecture, with the spotlight on Walter Gropius, Le Corbusier, Mies van der Rohe and Alvar Aalto. These were the founding fathers. He examines the roots of their ideas as well as the influence they had in shaping the modern movement. This later edition also includes a chapter on "Jorn Utzon and the Third Generation," which Giedion felt had successfully carried the principles of modern architecture into contemporary society.

Giedion also explores the shifts in attitude toward city planning in the late 19th century and early 20th century, reviewing such seminal figures as Ebenezer Howard, Patrick Geddes, Arturo Soria y Mata, and Tony Garnier, which ultimately lead to the creation of C.I.A.M, the International Congress of Modern Architecture.

Giedion is unabashed in his support of modern architecture, which has made this book the favorite whipping post of post-modern critics. But, few have explored the subject as deeply as has Giedion. Don't rely on other interpretations of Giedion. Read "Space, Time and Architecture" before drawing any conclusions.

I enjoyed this book for the author's insights into how 20th century architecture, starting from certain antecedents in the 19th century, such as the early iron-reinforced concrete structures of William LeBaron Jenny, progressed through Louis Sullivan, Frank Lloyd Wright, the Bauhaus school, and so on, up to the style which he calls "the hanging curtain of glass."

Giedion shows how this spectacular 20th-century building originated around the turn of the last century and how it's modern variations represent a triumpth of this type of design.

The basic principle, as exemplified early on in the Carson, Pirie, Scott, and Co. building in Chicago, is that as stuctural members receeded from the outlying masonry walls into the interior skeleton of the building, this allows the architect to open up the facade with windows, skylights, and other penetrating elements in order to let the maximum amount of air and light into the building. Eventually no real supporting structural members need reside on the outside of the building, and the aesthetic result is the "hanging curtain of glass" effect... Whatever one thinks of this type of building, it has become a major landmark of 20th-century architectural design in cities all over the world.

Giedion's treatment of Robert Maillart's graceful, parabolic spanning bridge designs in the Swiss Alps and some other places, such as the Tavanasa Bridge in the U.S., which he specifically discusses as one of Maillart's most important achievements, is also very interesting.

Overall, Giedion's book is a fine treatment of an important and difficult period in the history of architecture, and is one of the most important books on architecture to be written in recent decades.