Published in 1963, this book is Sergio Larrain's very first publication, that would soon become a seminal work for Chilean and Latin American photography. Published in the Cadernos Brasileiros series, in collaboration with the poet and cultural attaché at the Brazilian embassy Thiago de Mello, it subtly shows, through 44 pages, the photographer's vision of photography. 
For the first time, Sergio Larrain considered his work from a theoretical standpoint. "When I turn my gaze outward, camera in hand, I’m actually looking inward for pictures; I can only materialise that world of phantoms when I see something that resonates within me. Visible reality, the root of photographic endeavour, is also one of the vertices rectangular interplay: rectangle in hand (the camera), I seek geometry. Photograph: it (the subject), rendered geometrically". This definition, constructed like a syllogism and with a nod to the haiku, expresses the driving spirit that would reappear in his philosophical writings.
Republished as a fac-similé conform to the original, this version of El rectángulo en la mano, issued freely in a hardcover, with an essay by Agnès Sire, is a tribute to the Chilean photographer's emblematic book.