After his participation in the Arte/Cidade project in 1994, the artist Rubens Mano started a series of works with which he seeks to examine the correspondences between the construction of spaces and how we produce, experience, and activate spaces. Illustrated and bilingual (English and Portuguese), princípio ativo is a book that delves into Mano’s main works and actions over the years, interspersing them with an essay by researcher Aline Dias. The book is the result of a colaboration between Anozero – Bienal de Coimbra and the publishing house Ubu.