This book presents two interventions carried out by Laurent Sfar in 2010, one at La Maréchalerie, a contemporary art centre in Versailles, and the other at the Galerie du Granit, the national stage in Belfort. Both share a particular attention to architecture: around the organisation of the gardens of the Château de Versailles for the first exhibition, Les Arpenteurs [horizon 01], and the rehabilitation of the Belfort theatre led in 1984 by Jean Nouvel and his team for the second (L'hypothèse contrastive). The editorial and graphic structure of this two-entrance book, laid out head to tail, allows different readings and approaches to Sfar's work, the point of junction and rotation being at its centre, at the acknowledgements. The viewpoints adopted in the two parts, although radically different in content, are linked, answer and complete one another. A series of colour signatures reproduces the whole of the work done for the first exhibition, without text and often full-page, echoing the colour pages devoted to the second; between these image sequences are inserted two single-colour signatures containing Pierre Tillet's text and its English translation for the first exhibition and Nicolas Surlapierre's for the second, together with notes and documents that explain and nourish the pieces shown.