El tamaño de la forma is a significant architectural essay by the late Agustí Obiol. Originally penned in 2012 but unpublished until 2025, the book was finally released through the joint efforts of Cecília Obiol, the author’s daughter and Josep Lluís Mateo.

This book is a concise and engaging treatise on how structures work in architecture, written by one of Spain’s leading experts in the field.

Mateo’s involvement extends beyond publication; he actively participated in the book’s presentation and paid tribute several occasions.

Obiol, a distinguished professor of structures at the Universitat Politècnica de Catalunya (UPC) and co-founder of the structural consultancy BOMA, was renowned for his ability to bridge the gap between engineering and architectural design. In El tamaño de la forma, he emphasizes understanding the behavior of structures over merely calculating them, advocating for a science-based approach that prioritizes fundamental principles over technical procedures.