This book offers a detailed insight into the desire for, and consequences of, precise communications in the daily life of contemporary architectural practice through close readings of constructed architectural details by Sigurd Lewerentz, Caruso St John Architects, Mies van der Rohe and OMA. In the professionalised context of the contemporary architectural profession, precise communications - drawings, specifications, letters, faxes and emails - are charged with the complex task of translating architectural intent into a neutral and quantifiable language which is expected to guarantee an exact match between the architects' intentions and the constructed result. Yet, as any architectural practitioner will know, it is doubtful whether the construction of any architectural project may ever exactly match all written and drawn predictions. This book challenges claims to certainty which have been attributed to such communications from the mid-nineteenth century onwards, and critiques ongoing expectations of certainty in contemporary architectural production.