I am delighted to announce the release of my book «L’intelligence des formes», published by MētisPresses in Geneva. This book is based on the final results of my PhD research, carried out at the EPFL between 2014 and 2018 with Luca Ortelli and Elena Cogato Lanza as supervisors. It examines the collective housing initiatives developed at the beginning of the 20th century in Vienna and Frankfurt, considering Hof and Siedlung as two alternative housing models for the city. Vienna and Frankfurt are hence opposite but complementary phenomena, as much in their approaches as in results, both from an architectural and planning point of view. In line with these premises, this book recognizes Vienna and Frankfurt as "extreme polarities" through which it is possible to thoroughly understand the crucial role collective housing played in European history. This goal was achieved through re-drawings of original archival documents, drawn with the highest degree of homogeneity to ensure comparability. The book not only investigates these experiences from a historical point of view, but considers the case studies analyzed as fully-fledged urban organisms belonging to the contemporary city. This book is available also in an Open Access version, downloadable on the MētisPresses webpage.